Cast bullets for Mannlicher M95 in original 8x50R - keyholing!!

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cohenmj660 posted this 05 June 2023

Hi out there. I’m looking for some help with a very specific question and I have a lot of background, so my question is going to be fairly lengthy. In summary, I’m looking for why my bullets seem to be keyholing, and what can I do about it. Now the background: The firearm I’m using is a Steyr-Mannlicher M1895. It is chambered in the original 8x50R and still has the original 30” barrel. The bore looks fairly good, although it does show some minor pitting. Nevertheless, the muzzle end seems ok since a vintage military bullet only goes in part way.

First, what ammo doesn’t keyhole? I have about 40 rounds of vintage military ammo for this rifle. The headstamp shows the Bulgarian lion and indicates that they’re from 1936. The bullet is a steel-jacketed round nose and weighs in at 244 grains. There’s a cannelure near the base of the bullet into which the case mouth is crimped. I don’t know what weight or type of powder is inside. I recently went to the range and shot a 4-5” group (5 shots) at 50 yards. The hits were about 12” above the point of aim, even though I had the rear sight set as low it could go (300 Schritt). No keyholing.

Second, I have other ammo that I purchased from Gad Custom Cartridges. These are reloads made from reformed PPU 8x56R cases and have what appears to be 205 gr spire point bullets. Once again, I don’t know the weight or type of powder used. These seem to print pretty close to the point of aim using the same rear sight setting. Similar group size but no keyholing.

I measured the diameter of both of these bullets (i.e., the vintage military and the reloads) and they both measure 0.323”.

OK, now the problem. I made some reloads of my own. The cases are leftover vintage military (1936) that I decapped (Berdan) and reamed out the primer pockets to fit CCI 250 Magnum large rifle primers (I was not able to find any CCI 200 primers anywhere). The cases were full-length resized and I guessed at a charge of 45 grains of IMR-3031. The bullets are ones that I cast myself from a Lyman 323378 mould, using homemade #2 alloy (hardness measures 15) and 8mm gas checks. The bullets were sized to 0.323” (i.e., to match the other bullets that I described above). When I shot these at the range, I could barely find the holes until I saw a couple that were quite far away from the point of aim and totally keyholed.

OK, now, let’s talk about the diameter of the bullets, because this is a very common cause of keyholing. From what I’m able to read, the bore of these old M95 Mannlichers is 0.329 or 0.330”. I have read that even though the original 244 grain bullets measured 0.323” they were expected to obdurate during the firing process, thereby grabbing the grooves and stabilizing the trajectory. I have no way of knowing how much, if any, obduration either my vintage military or my Gad Custom reloads experienced. All I know is that for those two cartridge types, there was no keyholing. I haven’t yet had a chance to slug my bore.

So, even though a very common cause of keyholing is bullets that are too small for the bore, this didn’t happen with 0.323” bullets in the first two cases, only in my reloads.

So, my next question, is it possible that my own reloads are overcharged and forcing the bullet down the bore too fast for it to obdurate and grab the grooves? Does anyone have any powder data for this cartridge with a 240 grain long round nose bullet?

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Eutectic posted this 05 June 2023

Sounds like my first adventure with cast bullets in a 8mm Mauser.

First: you need to slug the bore. The major diameter on your bullets should be at least 0.001" larger than the groove diameter. As-cast bullets might work if their diameter is large enough.
Second: your charge is much too heavy. I would start about 23 grains of 3031 and work up.
Third: 323378 is a long nose bore rider. The nose MUST be supported by the lands. Drop a bullet nose first into the muzzle. If it drops in up to the bands the nose diameter is too small. Lyman 323471 has worked for me, but it might cast too small depending on your barrel.

Cast bullets are different from jacketed. Sounds like a fun project.

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John Alexander posted this 05 June 2023

Guessing at a load of  45 grains of 3031 is the biggest problem. Very bad guess.  Try about half as Eutectic suggests. You may have to so do serious deluding of your bore before trying cast again.

John

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Hornet posted this 05 June 2023

I think your sized diameter is way too small. For reference, Lee makes a C329-205-1R mold and 0.329 push-through sizer specifically intended for these rifles. I have heard of other people using them with sized-down 0.338 designs. I'd tend to agree with a load around 23 grains of 3031 and work up as needed.

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45 2.1 posted this 05 June 2023

 You are getting keyholing because your bullets are undersize. Measure the inside diameter of one of the cases you've fired in the rifle. It probably will take anything up to that size. I've worked with the remake of that rifle into the 8x56 and that rifle should take 0.329" bullets, but accepts 0.338" loaded and fired in it. You need larger bullets and try a milder load with Unique to see if you can get it running.

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cohenmj660 posted this 05 June 2023

Wow - thanks everyone for the quick advice. Lemme see if I can address a few of the comments.

First, re: John Alexander. Yeah, I was being a bit flippant with my post when I said that the charge of 45 gr of IMR-3031 was a guess. In fact, I took that right out of a post that I saw from, I believe, Cartridges of the World, Chapter 7, Military Rifle Cartridges in which a charge of 45 gr of 3031 was recommended for a 244 gr bullet as one that approximates the military load.

Second, re: Eutectic. I think my mistake is assuming that the charge for a cast bullet would be about the same as the one for a jacketed bullet of the same weight and shape. Apparently this isn't true, which is why you suggest starting at 23 gr. And, yes, I still need to slug my bore one day. However, I will say that the Lyman 323378 bullet that I made only goes into the muzzle end of the bore a short distance, so that's a good sign. In addition, remember that I was able to shoot two other bullets, both measuring 0.323", through that bore without keyholing. I think that means that there's something special about undersize cast bullets vs. jacketed ones.

I'll keep everyone posted once I slug the bore.

 

Mike

 

And thanks again for all your help.

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John Alexander posted this 06 June 2023

 Taking recommended charges for jacketed bullets out of any source, no matter how reliable, and using them a cast bullet won't work.

The difference between shooting jacketed bullets and cast is huge.

The fact that the two jacketed bullet cartridges shot reasonable and a cast bullet of similar diameters and Way to much powder is no mystery.

Bullet size is probably a factor as point out, but the perfect size cast bullet of #2 alloy will not work with full charge loads.

John

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cohenmj660 posted this 06 June 2023

Hi John,

Yup, a rookie mistake on my part. I've reloaded many a cartridge in the past, both with cast bullets (9 mm, .45 Long Colt and 357) as well as jacketed 30/40 Krag and .30 Remington, but never without the appropriate references in my Lyman manual. Now that I look at some of the entries (e.g., 8 x 57 mauser), I see that not only are the charges different for cast bullets but they also recommend different powders altogether.

Is there a reason why? I'm curious about the mechanism of the difference between cast and jacketed.

Thanks,

Mike

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delmarskid posted this 06 June 2023

Gas checked cast bullets work best for me at between 1600 and 2000 fps with a bullet that is a couple thousandths groove diameter. When cast bullets are undersized or driven too hard they won’t take on the spin they need to fly straight away. They just fly over the tops of the grooves I believe.

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longhunter posted this 07 June 2023

Ok,

So this has worked for me. I have had a couple of 8mm's that were over sized.  Early 8mm usually do. Go to 

Mid South Shooters supply.  8mm karabiner, It an over size mold of 215 gr. Lee mold #006-8mmKAR

or Mid South #006-8mmKAR. Size will help they run about .330. Hand  lube and gas check shoot as castor size and lube .330 

16 gr of 4227 or 2400 will work.

Jon

 

Jon Welda CW5 USA Ret.

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cohenmj660 posted this 07 June 2023

Thanks for the additional information. I'm going to slug my barrel as soon as i get a chance. This seems to be the critical piece of data that I need.

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cohenmj660 posted this 08 June 2023

Hi all,

I was able to make a decent slug by drilling an 11/32" (0.344") hole in a piece of wood, melting one of my old 58 cal Minie balls, filling the hole up with the Pb and cutting the resulting slug into two so that I could get duplicate measurements. The whole operation went off without a hitch in about an hour. Here are the results:

Slug #1: Grooves 0.329 and 0.330; Lands 0.313 and 0.316.

Slug #2: Grooves 0.330 and 0.331; Lands 0.313 and 0.314

 

In addition, I checked the bore with two drill bits that would ride on the lands, a 5/16" (0.3125") drill bit slid easily into the muzzle, whereas a 21/64" (0.3281") bit did not.

 

In addition, I measured the dimensions of my current bullets (Lyman 323378):

As cast: nose of bullet just in front of the first band 0.319-0.320", bands 0.326-0.327"

As sized: nose of bullet just in front of the first band 0.319-0.320", bands 0.323"

 

I'm thinking now that I might get decent accuracy with my current bullets if I reduced the charge and sized to 0.327". I'll probably start off with 12 - 13 gr of Unique and see what happens. If that doesn't work, I'll have to look for a mould that makes a 0.330" bullet (or slightly larger).

 

Once again, thanks for all your help,

 

Mike

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Duane Mellenbruch posted this 08 June 2023

Odd number of grooves or even number of grooves?

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cohenmj660 posted this 08 June 2023

Even; 4 grooves and 4 lands.

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Eutectic posted this 08 June 2023

Cohenm,

There are two major differences between jacketed and cast:

First the hardness of jackets is many times harder than the hardest lead alloy.

Second the melting point of jacket material is much higher then any lead alloy.

When black powder was king, lead and lead alloy bullets worked fine.
If you load smokeless powders to black powder pressures and velocities this still holds. 

Steve

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John Alexander posted this 08 June 2023

Shooting cast bullets from 0.002 to maybe much more under groove diameter is a pretty iffy proposition and may lead to record amounts of lead stuck in your bore.

If I were going to try it, I would cast the bullet of as soft an alloy as I could find such as 30 or 40 to 1, or pure lead, and use a small charge of very fast burning powder. Maybe 7-8 grains of Bullseye or equivalent.  And hope that the fast pressure rise would upset the bullet to groove diameter before too much hot gas got past the bullet and ruined my day. 

This bullet sounds like a candidate for paper patching or polymer coating to increase the dimeter to groove diameter or a bit more.

On the other hand if you are going to try it with #2 alloy and unique be sure and report your results we mayl all learn something. Conventional wisdom such as I suggested above is often wrong.

John

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cohenmj660 posted this 08 June 2023

Hi Steve - yes, the thing that I was not accounting for (when I observed that I obtained decent groups with 0.323" jacketed bullets but not with cast ones) is the potential for melting of the lead bullets. 

 

Hi John - I think I see where you're going with the suggestion to use a small charge of a rapidly burning powder. Since the 244 gr RN bullet is quite long, a sharp smack from rapidly burning powder may help the base of the bullet obdurate into the grooves better than a gentle push from a slow burning powder. As I don't have any Bullseye, I might try 700-X instead of Unique, since its burn rate is very close to Bullseye. My recollection is that there's a danger of either getting the bullet stuck in the bore or bulging the barrel if too little powder is used. Is that true, and if so, how does one know where to start?

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John Alexander posted this 09 June 2023

Mike,

700X should do.  I don't think 8 grains is likely to get a bullet stuck.  WHAT DO OTHERS ON THIS THREAD THINK?

Getting a bullet stuck in itself will not bulge the barrel.  Shooting another bullet with one stuck in the bore may. So peer thru the bore after the first shot if you don't see it on target. If a bullet is stuck drive it back out with a steel rod after you make sure the rod doesn't have sharp edges at the bullet end and is smooth and grit free.  A rod slightly under bore size is cheap at Home Depot.

I didn't say I was sure this would work -- only that it is what I would try If I had to use an undersized bullet.

I still think your best bet is a mold that will produce bullets the right diameter. The Lee mold suggested by longhunter would get you much closer to your groove diameter and could be easily beagled  to produce bullets slightly over groove diameter -- and it is cheap. 

John

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Ken Campbell Iowa posted this 09 June 2023

besides sticking bullets in your barrel ... another reason to not go too slow .. is

that you need to spin the bullet fast enough to properly stabilize it ...  as it gets too slow the bullet starts to make bigger groups, and then even slower will start to show elongated bullet holes.

**********************

especially with longish bullets ... I am guessing that with your current bullet you need at least 1300 fps to keep it in a safe velocity range.  Unique is good in that range ... guessing 7 or 10 grains to start ...   a side benefit is that at these lower velocities you can do well without gas checks on the bullet.

******************

***************

also, just in case you wake up in the middle of the night and wonder how the heck a bullet bigger than the groove diameter of your barrel could possibly be better ....   gotta be distorted, right ?? ... you are correct ...   

however it is a compromise in trying to get the bullet a straight launch from your chamber ...specifically the throat ....  the better the bullet fits the throat, the fewer screwy and mysterious problems you see on the target ...  most throats are bigger than the groove diameter ... in an effort to chamber easily in hunting or military use ... mostly the better end of the compromise is to have the bullet fit snug in the throat even though it will have to be squeezed down when it gets into the main barrel ...  even 0.003 or so diameter difference ...  >>>>  the squeeze-down ... and distortion ! ... is still better than a groove sized bullet bouncing around and launching sideways from the throat.   .................. it could be that metal jacketed bullet resist or unbend themselves, but non-plastic lead bullets once bent in the throat just remain bent and unbalanced all the way to the target.

and military or worn throats can be a bunch bigger than the groove diameter ... we need more tests to find out just how much diameter difference there could be before the compromise turns around.   

... and yes, a throat diameter near the groove diameter is a great thing for accuracy ... but not available in commercial rifles. ... and needs precise ammunition to avoid jams.

just some thoughts, please keep us informed of your adventures ...

ken

oh, 70 years ago when I started casting, I had a list of 40 things to worry about for cast bullets ... now I have a short list of 3 or 4 things ...  covers 99 per cent of the way to reliable 2 moa groups.  couple of those things I mention above ... I can't remember the other things ...  oh wait ... LUCK !

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cohenmj660 posted this 09 June 2023

Thanks again guys. I hear the feedback loud and clear regarding trying to cast bullets at, or slightly above, groove diameter (0.329-0.330" in my case). In addition, shorter bullets, e.g., in the 170-180 gr range for an 8 mm RN bullet, naturally stabilize easier at lower speeds. I will start looking for a mould that fits those requirements. The challenge I see now is finding a lube/sizer die for that diameter bullet. I have an RCBS Lube-a-Matic, currently set up with a 0.323" die. This sizer takes Lyman dies as well. I've been poking around on the internet and, so far, I can't find a sizer die in the range of 0.329". I realize that I could probably use the bullets as cast if I'm careful with the as cast dimensions, but then, how do I lube them properly? I realize that there are all sorts of methods for lubing in a pan or by powder coating, but from my experience, the best way to lube the bullets and swage the gas check is using a lube/sizing press.

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Duane Mellenbruch posted this 09 June 2023

You will probably find that applying a soft wax lube by hand, rubbing the lube into the grooves a bit messy and seem slow.  But it gives you a chance to inspect the bullets and as you wipe and massage them, tell them that they are well cared for and will fly straight and true.  While it may not work, it will give you something to think about if you get bored.  If your bullet lube requires a heater, hand lube might be a problem.

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alphabrass posted this 09 June 2023

I opened up a .323 Lee Push Through die to .328 using abrasive paper and a split wood dowel.  Used a drill press, but a hand drill could be used also.  Started with 320 grit and finished with 600 grit.  It opens up pretty fast.  I used pin gages to monitor the progress.  The bullets are pan lubed and then sized.

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cohenmj660 posted this 17 September 2023

Hi all,

Well I finally made it to the range on a couple of weeks ago and obtained very encouraging results. I brought 6 lots of reloads with me, all made from vintage (1935 or 1936) military 8x50R Austrian cases that I modified to accept modern CCI primers, and all with cast 240 gr RN bullets sized to 0.323" (Lyman 323378 mold). They consisted of 4 rounds each of 8, 10 and 12 gr 700X and 8, 10 and 12 gr Unique powder. The results were very similar for all 6 lots.

First, there was very little recoil; these are truly plinking combinations of powder and bullet weight. Second, the velocity was quite low; I estimate that it took between 1/2 and 1 second to travel the 50 yards to the target. This is only a few hundred feet/sec. To make up for this, I had to set the rear sight to 600 Schritt (~500 yards) to get near the bullseye. Nevertheless, I did obtain respectable grouping. I've attached a picture of one of my targets, This one was typical, 8 gr Unique at 50 yards. Note: the keyholing problem was not present.

I'm still not convinced that I couldn't do better if I had bullets sized to 0.329", but at least this gets me off to a decent start. Also, I think I may need to knock my front sight over to the right a tad.

Thanks again to all the members for all your help,

 

Mike

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Duane Mellenbruch posted this 17 September 2023

Now that you have established a few facts about the barrel, you could do a chamber cast.  It would not be unusual for older rifles to experience throat erosion which enlarges the area in front of the chamber.  Some just want to get the "ol girl to go bang".  Others might want to invest a little more time to see just how good the accuracy of an old rifle can be.  Sometimes this can be as simple as seating the bullet a little further out so the nose of the bullet is very close to engaging the lands.  The important thing is to enjoy the journey.

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Larry Gibson posted this 17 September 2023

Get the Lee Karabiner mould and the Lee .329 sizer.  The sizer will probably come with LLA (Lee Liquid Alox bullet lube).  Your #2 alloy will work fine.  Size and lube the bullets as per Lee's instructions using 2 light coats and letting the LLA dry thoroughly before using.  Those bullets with 3031 (yes start at 23 gr and work up until accuracy once again goes south.  That will probably be around 1950 fps +.  The LLA will do its job up through that velocity.  You might also consider using a dacron filler.  If you really like the rifle, you might consider a mould from NOE or Accurate that is PB'd and weighs as cast in the 150 - 175 gr range.  Loaded over Bullseye, Red Dot or 700X it would make an excellent small game/plinking bullet.

Your first load with your cast bullets (45 gr 3031) wasn't melting the bullets or stripping in the rifling.  The velocity was simply what to fast for a cast bullet in the probable 10" twist barrel of the rifle.  Has to do with the bullet exceeding the RPM Threshold.  The undersized jacketed bullets gave poor accuracy (5" groups at 50 yards) for the same reason....too much RPM for the unbalanced (not to be confused with instability) undersized bullets. 

LMG 

 

Concealment is not cover.........

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MP1886 posted this 17 September 2023

Larry I think you're off on this one.  The original bullet was .321 and 244 grains which is a very long bullet. I know you said cast, but think about shooting the Lyman .323  323471 in the 8x57 Mauser which has even a faster twsit then 10 and how accurate that bullet shoots especially at long distant and I might as well over 2000 fps. The OP's problem is that his cast bullets aren't fat enough.

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Larry Gibson posted this 17 September 2023

MP1886

No idea where you come up with ".321"?  OP states; "The bullets are ones that I cast myself from a Lyman 323378 mould, using homemade #2 alloy (hardness measures 15) and 8mm gas checks. The bullets were sized to 0.323” (i.e., to match the other bullets that I described above). When I shot these at the range, I could barely find the holes until I saw a couple that were quite far away from the point of aim and totally keyholed." 

OP then slugs the bore and comes up with; 

"Slug #1: Grooves 0.329 and 0.330; Lands 0.313 and 0.316.

Slug #2: Grooves 0.330 and 0.331; Lands 0.313 and 0.314"

The OP is using a Lyman 323378 which has minimal bearing surface drive bands and a very, very long bore riding nose. There is no comparison with it and a 323471, a Loverin bullet, sized to fit a .323 barrel.  The OPs bullet sized at .323 and shot in a .329 barrel with a load of 45 gr IMR 3031 is pushed way too fast.  The drive bands with only about half their purchase on the lands might also be stripping under that load.  

The OP, with his cast bullet, has two problems; the undersized cast bullet and pushing the bullet too fast, I.e. to too high of RPM.  With the jacketed .323 bullets in the .329 barrel the bullets probably had considerable wobble and may have obturated which would have increased the imbalances in the bullets.  Thus, again, the high RPM would account for the large group dispersion of 5" at 50 yards.  

LMG

Concealment is not cover.........

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MP1886 posted this 17 September 2023

The .321 eas a typo.  The original jacketed bullet for it basically rode the lands.  The bullet he chose was entirely the wrong bullet. With very little bearing band and the fact he was shooting an undersized bullet in addition to the bore riding section just free floating around the bore it's very possible it skidded some and the rifling didn't get a good enough hold on the bullet to spin it proper.  The comparison I made to the 8mm 417323 wasn't a comparisson of the bullet style, but to the lenght of the bullet and that is what the twist is judged off of.  In other words both bullets were very long and Steyr, plus other's that manufactured those rifles put the proper twist in them.  His bullet keyholed simply because it DIDN'T FIT right at all.  It's not an rpm issue. 

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Ken Campbell Iowa posted this 17 September 2023

congrats ! ... you are in the ... fun  ... part of the tunnel ....  the light is getting brighter and if you are after hunting ammo you might be there already ... a 240 gr bullet at 1300 fps is a decent deer load ...  compare to a 357 magnum ... and 3 moa is ok for most deer hunting.

your loads of 12 gr Unique or 700X .. are probably a little faster than you think .. i enclose a snippet of  STARTER load data that should be close ... this for a 215 gr 8mm bullet  ....   your 240 gr is likely just a tad slower ...  but better than 600 fps.

*************************************

again, for best accuracy, usually it is best to get a snug fit in the THROAT ... the common advice of "  a few thousandths over groove diameter " ...  is a nice try for a new commercial sporter ... might be close to throat diameter ... but old military chambers ...  or a high shot count deer rifle .. might have a throat that is 3 or 6 thousandths over groove diameter .

best to do a chamber and throat image with a lead slug or cerrosafe ...  also tells you about seating depth ...  the half hour it takes to do this will save you much more time ... and funny results ...in the future ...  

***************

once you have the rear of the bullet plugging up the throat ... then you can address the front end of the bullet fit to the grooves ... ideally, as for match shooting,  the same diameter as the lands ... light land marks on a unchambered bullet ...

but at least the nose should be no more that 1 thousandths smaller than the lands.  

****************

as an example, my favorite/lazy plinking 30 cal plinking ammo in my factory deer rifles is a 130 gr plain base that I find cheap enough to buy by the 500 box to kill pop cans at 40 yards ... it has a great 0.310 base but only a 0.297 nose ... so it is doomed to about 3 moa out of the box ...   if i want better i need to dig out a fatter nose mold and cut the groups in half.

hope this helps

ken

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Larry Gibson posted this 18 September 2023

Yup, OP dropped the velocity/RPM and he is "in the fun part of the tunnel".....plum amazing how that works.....

LMG

Concealment is not cover.........

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MP1886 posted this 18 September 2023

Yeah plum amazing, but it still isn't the rpm of the bullet it's the FIT!.  It's okay to be wrong sometimes larry.

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cohenmj660 posted this 18 September 2023

Hi all,

Thanks for all the great advice. I have a few questions:

1) Larry refers to me as OP. Is that something like Original Post(er)? You can call me Mike.

2) A few of you have suggested that I do a chamber and throat image with a lead slug or cerrosafe. Is there a procedure for doing that?

3) Yes, perhaps i did make a wrong selection of my mould. I mistakenly thought that I would get good results from a bullet that looks very much like to original 244 gr steel jacketed long nose bullet that was developed for this rifle. See comparison below. And, I get it, there is very little surface area of my cast bullets that can ride in the grooves, even if sized correctly.

3) As for stabilizing the bullet with the proper rate of twist, well, obviously I should measure that in my particular rifle (one day). But, if I stick with a bullet that's essentially the same shape and weight as the military load, wouldn't that be self-correcting?

4) Thanks to Larry for suggesting a starting load of 23 gr IMR-3031. I should be able to work my way up from there.

5) As for checking the barrel on these lighter loads, I had planned to do that at the range, but found it unnecessary due to the puff of dirt/sand from behind the target with each shot.

6) What's a dacron filler?

7) One other thing; I only have 35 of the original military rounds left in my collection. I'm saving as much of the brass as I can by drilling and reaming out the primer pockets to accept modern primers. But, I also have a few hundred once-fired 7.62X54 Russian cases that can work nicely in my rifle. Another future project.

Thanks again, all,

Mike

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MP1886 posted this 18 September 2023

 Mike I'm sending you a link by private message.  I believe it will help you a lot.  Let me know if you can open it. 

MP1886

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Larry Gibson posted this 18 September 2023

Mike it is, glad to meet you.

Out of curiosity, what's the diameter of that original bullet? 

Here is a discussion I posted many years ago that explains what a dacron filler is and how I use it.

"I have for many, many years found dacron (polyester fill) to be the best "filler". I use a filler only when appropriate. Many think I always use a filler with every powder....I DO NOT!!!! The use of the filler can cause problems if not used correctly and when appropriate. If the powder is not correct for the bullet/cartridge combination then the filler is not going to make it "right". Many want to use a specific powder for a cartridge because the powder is "cheap" or because "they have a lot of it". There are lots of powders that are not only poor choices to use but that can be dangerous if used in an inappropriate bullet/cartridge combination. Do yourself a favor if you are wanting to use an inappropriate powder (usually "no data" available is an indication the powder might be inappropriate) and get an appropriate powder. You will save yourself a lot of frustration. The use of the dacron filler only makes an appropriate powder perform better. The dacron filler will not make a silk purse out of a sow's ear.

Also many do not understand the difference between a “wad” and a “filler”.  A wad is a material pushed down on the powder to hold it in position against the flash hole.  There is a gap between the wad and the base of the bullet.  A “filler” fills the entire space between the powder and the base of the bullet.  The filler will not move under recoil or rough handling of the cartridges.  The use of a appropriate filler prevents migration of the powder through or around it.

I don't use the dacron filler with the fast to medium burning "fast" pistol /shotgun type powders. I find one of these fast burning powders that is fast enough to ignite and burn efficiently at the velocity I want and avoid using a filler with them.

I almost always use the dacron filler in rifle cases with the slower “fast” burning powders (4227, 4759, 5744, 4198, etc. with lighter medium weight bullets for the cartridge; i.e. 140 - 165 gr bullets in .30/.31 cals of 30-30 through '06 case capacity), the medium burning powders (RL7, 3031, 4895, etc.) up through the slow burning powders (RL19, AA4350, H4831SC, RL22, 3100, etc.) that give around 80% or less loading density under medium to heavy weight bullets for the cartridge; i.e. 170 - 220+ gr bullets in .30/.31 cals. Those examples are for the .30/.31 cals but the same guidance applies to other calibers. The dacron filler is used only between the powder and base of the bullet.

The “dacron” is polyester fill as commonly found in pillows and toys. It also comes in sheets called “batting”. It can be obtained very reasonably at most any fabric store.

The dacron batting comes in various thicknesses. I prefer that which is about 5/8" thick. My wife recently bought me 10 yards which will give many, many thousands of cast bullet loads. With this current batch of batting I cut it initially across the width into strips about 3/4" wide. I then "eyeball" cut 1/2" wide chunks which is close to 3/4 gr.

A smaller chunk is cut for 1/2 gr and larger for a larger amount. I've cut some chunks that weight 1/2, 3/4, 1, 1 1/4 and 1 1/2 grs and have them in a "snack" baggie stuck on a poster board above my loading bench for quick reference when I need to cut new chunks. The batting will run thin and thick throughout the sheet so I again just "eyeball it" based on the thickness of the batting when cutting the chunks.

Pretty extensive tests have demonstrated that the weight of the filler does not have to be exact, only close. What is important is that there is enough so that it “fills" the space between powder and bullet. A little too much hurts nothing but too little poses problems. That's why I have the different size "chunks" so I can use the right size for the case capacity I am filling. For example; with most medium burning powders (3031, 4895, 4064) in and '06 to function an M1 a 3/4 gr dacron filler is about right. With slower powders that give a higher loading density like 4831 a 1/2 gr filler is about right.

I use a section of .22 cal cleaning rod in cartridges of .30 - .375 cal to push the Dacron chunk inside the case just so it is all in. The 6 to 10" section gives plenty to hold onto and sufficient "feel". Merely hold the chunk of dacron over the case mouth and shove it in with the rod. Sometimes it takes a couple three pokes to ensure all is inside the case mouth. I poke the chunks in until all the dacron is at the bottom of the neck or at least all in the case. It doesn’t matter exactly where just so long as you don’t tamp it down on the powder as a wad and leaved a space between the base of the bullet and the dacron.

  What you want to do is push it in to let the base of the bullet finish pushing it down and adding any compression against the powder. Thus I do not push it down on the powder but let the bullet do that when the bullet is seated. Using the right size chunk of dacron this method then provides a "filler" in the air space between the powder and base of the bullet.

A small length of coat hanger works for the .22-7mm cartridges and an unsharpened pencil works well for .45 cals. With the charged cases in a loading block I simply hold the chunk of dacron over the case mouth and push it in with the rod.  It is quite easy and a lot of “precision is not required, just get the dacron into the case and let the bullet finish pushing it down.

LMG 

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cohenmj660 posted this 18 September 2023

Hi Larry - thanks for the training lesson on dacron fillers. I'll have to see about that once I start with loads that leave substantial space in the case, although, I have to admit, the last 6 lots that I made with 700X and Unique were pretty much empty.

You hit the nail on the head with your question about the size of the original bullet. Those bullets measure 0.323 - 0.324" at the base and ~0.320-321" right in front of the cannelure. In addition, I had read somewhere that these bullets would "obdurate" so that they would fill up and seal in the bore, which was typically 0.329". Silly me...I thought that if a steel-jacketed bullet would obdurate sufficiently to seal up in the bore, why shouldn't a lead (OK, #2 alloy) bullet do the same?

I think the whole obduration thing might be a myth, at least as far as the M96 Mannlicher goes with those steel-jacketed bullets and the pressures that those cartridges developed. This may explain why, when they reworked many of these rifles between the worlds wars they chambered them to accept the more powerful 8x56R cartridge which sported 0.329" bullets (as is sold by PPU these days) without modifying the bores at all.

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Larry Gibson posted this 18 September 2023

Mike

I seriously doubt the #2 alloyed cast bullets with700X and Unique powder loads obturated much. Note it is "obturate' with regards to bullets sealing the bore not "obdurate" which has a completely different meaning.    

As I said in a previous post to MP1886,  "The OP, with his cast bullet, has two problems; the undersized cast bullet and pushing the bullet too fast, I.e. to too high of RPM."   You solved the second problem (too high a velocity with too much RPM) with the 700X and Unique loads.  When you get that bullet or, perhaps, the Lee Karabiner, to fit the throat and/or groove diameter then accuracy should improve a good deal more.

LMG

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MP1886 posted this 18 September 2023

Mike I pushed the 8x50R's brother to 1900 fps and over in the 8x56R in my M95 Steyr.  Those two rifles aren't subject to rpm problems.  To name a rifle that is difficult because of it's fast twist it's the 6.5x55 Swede. Don't far into that trap friend.  For as undersized as your bullets were and pushing them fast that wee little bearing surface had a hard time holding onto the rifling, nothing to do with rpm. 

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Ken Campbell Iowa posted this 18 September 2023

chamber image ... here is a copy from a post i made a few years ago ...  i find the lead upset is easiest for me ...  and it gives me a " loaded brass " that i keep for future reference ...   i bot some lead swaging wire .. you need pretty soft lead, as in pulling the bullets from 22 rimfire cartridges.  melt some 22 bullets all together in a spoon and roll or hammer that lump into a 1/4 inch round worm to insert into your test brass case.

use a brass or aluminum rod to pound so to not scrape your barrel.  POUND WITH A HUNDRED LIGHT TAPS .. gives the lead time to swage ...

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a simple throat check is to seat your chosen cast bullet loosely and very long ... chamber it and see how far ( or if ) the throat pushes the bullet back in the case ... that gives you an idea of the length of the throat ... it is often best to seat the bullet out as far as possible ... not always, but often.

the best ... and highly suggested method ... is to create an image of the entire forward part of the chamber including the throat and even a 3/8 inch portion of the rifling ahead of the throat.  this will give you a lot of information .  can/will save you weeks of random trying things that won't work .

use the search button here to look for posts on chamber casting ... chamber images ... cerrosafe ... chamber upset ... pound cast ...

cerrosafe is some neat stuff ... it melts at hairdryer temps and you gently pour the liquid into a pre-heated chamber ....stopping the flow with a wadded patch about 1/2 inch in front of the throat .  let it set up and then push it back out and you can see what your chamber looks like ....  you can order cerrosafe from rotometals, and you can use it over and over ... but i suggest you do a cast for every gun and store it for reference.

* pound casts * involve upsetting soft lead in the area of the front of the neck and into the rifling ...  i put a spacer rod into an empty case so i don't need so much lead and chamber the case  ... the soft lead should be a soft rod  seated in the neck and extends an inch or better up the throat before you tap it from the muzzle with a brass or aluminum rod ( softer than barrel but don't bugger a good cleaning rod  ) ... use about a hundred little taps rather than 5 giant hammer blows .  this gives a good image also; i keep soft lead wire around for this purpose , you can use 22 rimfire bullets also , melted into a rod shape first .

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cohenmj660 posted this 19 September 2023

OK, so lemme see if I understand this. I should start with a spent 8x50R case and put a spacer into the case so that there's about, what, 1/2" of space in the case mouth. Then I should make a rod of soft Pb that's about 0.300" in diameter and about how long? I can do this by drilling a hole in a piece of wood using a 9/32" drill, pouring the Pb into it and then punching out the slug out from the other end.Then I fit the slug into the mouth of the case that has the spacer in it and chamber the case.

Now what you're saying is that by 100 little taps on a 1/4" brass rod from the muzzle end will deform the Pb to the point that it takes on the shape of the throat and some of the rifling. Is that correct?

One other question - how do I get the case out? I'm picturing that if i work the bolt back the case (and spacer) will eject, leaving the Pb slug in my chamber. Does that happen?

Sound right?

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MP1886 posted this 19 September 2023

Mike you  make the lead cylinder as long as far as your want to measure.  I usually go into the rifling a little bit as that ways I get the throat, the leade, and some of the rifling.  You want to use the largest diameter rod that fit in the bore (which is the land tops, not the groove).  I usually put a marker pen mark on the rod at the crown before I stop just to see how much I compress the cylinder.  First start off by cleaning your chamber and bore.  Put a very light finger lube of light oil on the slug. You can tell by the sound of your taps when it's fully compressed as it changes from the first taps to the last. Also you would probably have to keep tapping as your open the action as these things fit tight sometimes. For the filler in the case I use to cut off a bolt that would fit inside the case neck, but having a lathe now I make a shaft.  Try to use as pure lead as possible as it compresses easier.

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cohenmj660 posted this 19 September 2023

Sounds like some good advice. I will try that once I locate a good source of soft lead. Does anyone have experience with using fishing weights for a source of lead?

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MP1886 posted this 19 September 2023

Old fishing weights maybe, but the ones you buy today are zinc!!!   If you had some Hornady round balls for muzzleloaders and cap n ball revolvers they are of soft lead. 

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Ken Campbell Iowa posted this 19 September 2023

22 rimfire bullets are soft ... but you have to melt them all together into a worm ... if you just drop a few down the barrel your upset piece will be kinda ugly.

and watch for the sound of your tapping to change suddenly as the lead is fully compacted ... if you keep going there will be a lot of lead extruded past the tip of your undersize push rod.  no big deal, but a bit ugly.

this whole procedure is actually pretty simple .. once you have done one ...

and yes, unlock the bolt and tap the sample out with a few more taps of the push rod.

oh, while tapping hold the rifle by the barrel,  no use beating up the bedding of the gun.

ken

 

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MP1886 posted this 19 September 2023

 I believe 22 bullets have a wee bit of antimony in them so they swage better. 

What I do is drill a hole in a well ages piece of oak that is larger then I need and use that for my mold.  Then wacking it on my anvil it pops out into a towel.  Then I chuck it in the lathe and turn it down to the precise size I need.  That way I don't have excessive pounding.  For taps and she's compressed.  

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hpbear101 posted this 19 September 2023

 

I have the 8x50 and a 8x56, I use the lee .329 mold in both. For the 8x50 I use 7.62x54R brass, it is slightly long you can trim to the right length or shoot them as is in most 95s. I have good luck with Herco and 2400. 

 

Tom

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MP1886 posted this 19 September 2023

If you use 7.62x54R for the 8x56R then they are really short.  The 8x50R isn't as bad.  That LEE .329 bullet is not fat enough for my M95 8x56R as the groove is .330.  So I got a mould for the 338 Win Mag and it sized down just beautiful and shot really really good.  As I've mentioned pushed it to almost 2000fps and had zero rpm problems.  

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Larry Gibson posted this 19 September 2023

"As I've mentioned pushed it to almost 2000fps and had zero rpm problems."  

And you shouldn't have as "almost 2000 fps" out of the 10" twist of those rifles is "almost" just 140,000 RPM.  The RPM Threshold is generally 120-140,000 RPM but may be pushed up some with a proper fitting cast bullet, especially in rifles with deep grooves like the M95s.  Actually, if only shooting at 50 or 100 yards, respectable usable accuracy can be gotten at a bit higher velocity with cast bullets. 

However, if just punching paper or plinking such velocities are not needed and not even desired many times.  Higher end velocities are most often wanted for hunting and shooting at longer ranges.

LMG

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MP1886 posted this 19 September 2023

....but yet the OP with the same twist and same bore/groove diameter problem was too small a bullet and rpm, yeah right.  Make up your mind Larry.  We aren't talking about 6.5 Swede or 7 twist AR15.  How about we agree to disagree before the thread disappears or gets closed. You want to agrue with me take it to pm's. 

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cohenmj660 posted this 20 September 2023

Larry and MP1886, I'm finding this debate fascinating, yet somewhat hard to follow. Let me see if I'm understanding the basics here. From what I read from Larry above, there is some sort of limit  as to how much spin can be imparted to a bullet, and that is in the range of 120,000 - 140,000 rpm. Is that correct? If so, what happens if one attempts to exceed that limit? Is it that the rapid increase in angular momentum of the bullet is just too high and the bullet skids across the grooves? Or is something else going on that limits the rpm? Does this limit also apply to jacketed bullets?

Going back to MP1886's example: 2000 ft/sec x 12"/ft x 60 sec/min x 1/10" (rate of twist) = 144,000 RPM. This puts the example cited by MP1886 to be slightly higher than the max 140,000. Is this what the disagreement is about (i.e., that Larry claims a limit of 140,000 RPM whilst MP1886 says he gets good accuracy even when exceeding that limit)?

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Larry Gibson posted this 20 September 2023

First of all, the RPM Threshold of 120-140,000 RPM is not a "limit".  It can be raised or lowered.  

Perhaps this explanation will suffice to enlighten you on the actual definition of the RPM Threshold.

The RPM threshold occurs at a point when;

[I]the bullet is unbalanced or becomes unbalanced due to uneven obturation in the bore or canting in the bore with ill fitting bullets during acceleration. The unbalanced bullet is forced to conform while in the barrel and its center of mass is revolving around its geometric center. When the bullet is free of the barrel's constraint, it will move in the direction that its mass center had at the point of release. After exiting the muzzle, the geometric center will begin to revolve about the center of mass and it will depart at an angle to the bore (line of departure). At 54,000 RPM to 250,000 RPM, depending on velocity and twist, the centrifugal force acting upon any imbalance in the bullet can be tremendous. It will result in an outward or radial acceleration from the intended flight path (line of departure) and will try to get the bullet to rotate in a constantly growing helix more noticeable as the range increases.[/I]

 

"Try to" are the key words here as there are things we do (slower burning powders, harder alloys, better designed bullets, perfect fit, etc.) that we do to push the RPM threshold upward. Conversely, using a faster powder, softer alloy, no GC, etc) lowers the RPM threshold. When the bullet goes beyond the RPM threshold it does not lose "stability”. It still is flying point forward. Its flight path simply becomes a larger expanding helical one. This is why when the RPM threshold is exceeded the groups expansion as range increases is non linear.

 

With cast bullets the RPM threshold will be exceeded long before the centrifugal force is enough to "spin the bullets apart". Exceeding the RPM threshold becomes apparent by the decrease in accuracy as velocity increases and the non linear expansion of group size as range increases

 

Thus, if the RPM threshold (normally in the area of 120 - 140,000 RPM....where is dependent on numerous factors) is crossed accuracy suffers, particularly in a linear expansion of the group size as the range increases.  However, as previously discussed in numerous other threads on the topic the RPM threshold can be moved up or down by varying several factors.  I have thoroughly demonstrated this numerous times using a 10" twist .308W rifle, with 3 different bullet designs suitable for the purpose using #2 alloy and using slow burning powders.  Pushing those bullets to 2200 - 2300 fps at 45 - 48,000 psi) at 167 - 178,000 RPM they have held 2 moa accuracy (just about the accuracy level the rifle is capable of) or less to 500 yards. 

 

LMG

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Larry Gibson posted this 20 September 2023

As an example of the non linear group expansion as the range in crease, here is a test conducted with the 311291 cast bullet shot with two different loads out of a .308W w/10" twist barrel.  

This is the groups at 50, 100 and 200 yards with the load that is under the RPM Threshold at about 133,000 RPM +/-.  Note the basically linear group size expansion as the range increases.

 

Here is the 50, 100 and 200 yard groups with the load that exceeded the RPM Threshold. This load was around 165,000 RPM +/.  Notice the large non linear but yet still "usable" groups by many at 50 and 100 yards.  Then look at the 200 yard "group" which had to be shot on a much larger target.  That is a perfect example of what happens when the RPM Threshold is exceeded.

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Larry Gibson posted this 20 September 2023

Looking at that last 200 yard target, note the bullet holes are all round going through the target even though the RPM Threshold for that bullet in that twist barrel was exceeded. That tells us bullet stability was not the issue.  As I mentioned in an earlier post we should not confuse the adverse effect of exceeding the RPM Threshold with bullet stability.  Let me also say again the RPM Threshold is not a "limit".  Interesting that the 200 yard group of the 1st load was smaller than the 100 yard group of the second load.

As to your first cast load with the too much 3031 powder the ill fitted cast bullets were probably borderline stabile but the too high RPM exacerbated that causing them to not only keyhole but also caused the very wide dispersion of the keyholing bullets.  If you get a better fitting bullet such as the Lee karabiner and slow the velocity RPM down then you should see an improvement in accuracy.

LMG

 

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