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

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Last Post 20 September 2023
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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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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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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.

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

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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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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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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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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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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.

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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

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

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

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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 ...

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

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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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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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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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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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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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