What makes an accurate cartridge?

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Last Post 21 April 2010

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mlr1m posted this 03 February 2010

I have been thinking about a new rifle for 200 yard shooting or a bit more. I want this for cast bullets using quality aperture sight. The rifles I have now are 40-65 and 45-90 and I was thinking something smaller. A single shot rifle is preferred.

After looking at different cartridges the 32-40 stands out as a nice dual purpose one. Capable of super accuracy and still a good hunting round. What makes this cartridge stand out over a 30-40, 30-30 or such? The 40-65 and the 45-90 have spoiled me as far as accuracy goes. If I can scrape up the bucks I would want a 30 or 32 caliber that could give them a run at 200 yards.

Michael

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JetMech posted this 03 February 2010

To my way of thinking, case capacity versus bore diameter has alot to do with it. Using progresive burning powders, the 32-40 would tend to have a lower peak pressure, as well as a slower rise to peak pressure. This translates to a gentler, more consistant force on the base of the bullet. Properly matched case capacity, bore diameter, bullet weight and powder burning rate will lead to the most consistant muzzle velocity.

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Lefty posted this 04 February 2010

Its hard not to be a fan of the 308 if rimless case designs are on your list. Personally I would like to find a pristine Model 70 target in 3006 for that matter.

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mlr1m posted this 05 February 2010

Lefty wrote: Its hard not to be a fan of the 308 if rimless case designs are on your list. Personally I would like to find a pristine Model 70 target in 3006 for that matter.

If I were considering a bolt action I would probably go with a nice .308 with iron (target)sights. I do have an old rem 700 in .270 that I have considered re-barreling to a 6.5x55 or .308 heavy barrel rifle.

I had been looking at another Sharps,this one in 30-40, but have decided it would not make a good target rifle. For some reason the 30-40's are not tack drivers im told. Even the rifle makers who make them agree to that.

Michael

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JSH posted this 05 February 2010

Tack driver? I guess it depends on what kind of groups you want or expect. From your original question, are you wanting to go with a modern design or any early smokless or BP style caliber. What platform do you want to build or buy this rifle on? If you are set on a Sharps or early design such as that I will let others comment. A modern design go with a TC and buy a custom barrel. The Krag may not be a “best” choice would draw an up roar in some crowds. The only 30-40's I have are of military types and shoot cast very well. Curious as to what kind of groups you expect to get from this rifle, what are you getting from the 40-65? jeff

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mlr1m posted this 05 February 2010

I would like a caliber that is capable of keeping 10 shots inside 3” at 200 yards. If a singleshot I prefer the old classic designs. My original thought was something that would be more economical to shoot. The 540 and 410 gr bullets I shoot know eat alot of lead and powder.

It is probably out of my reach right now as i'm on a fixed income but i'd rather try saving for a nice rifle over something I will be wanting to replace later on.

Michael

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mlr1m posted this 05 February 2010

The Krag may not be a “best” choice would draw an up roar in some crowds. The only 30-40's I have are of military types and shoot cast very well. Curious as to what kind of groups you expect to get from this rifle, what are you getting from the 40-65? jeff

I forgot to address the 30-40. I have an old 1898 springfield. It is not capable of shooting with my 40-65 or 45-90, granted it does not have the quality sights they do and is not in the best condition.

Michael

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RicinYakima posted this 05 February 2010

Michael,

Other than a small case capacity compared to bore, case design, IMHO, a little to do with accuracy potential for cast bullets. Quality of the barrel and chambering job is the first rank, followed by action type, stock fitting and sights.

Go to the home page of this board, look under screamer awards for different classes at the bottom of the page, production rifles are about 2” at 200 yards.

Ric

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CB posted this 06 February 2010

IM not so HO I believe Ric is right on. I would go a bit further and say that evidence is lacking to show that a small case capacity compared to bore size is necessary for match winning accuracy.

It makes some sense to to have a modest case capacity for the bore size. The top heavy and UNR shooters usually shoot something like the 30BR instead of 300 Win. mags. It saves some powder for a given bullet and velocity. That in turn saves money (always on the mind of cast bullet shooters) and also reduces recoil a tiny bit since a little less weight is shooting out the muzzle.

But the best production shooters (almost all shooting 308's with a lot more case capacity) do almost as well as the heavy and unrestricted shooters while shooting production guns as opposed to $3,000 custom benchrest rigs. This casts doubt on the assumption that 30 BR is much superior. I wish somebody that knows how to shoot would build and shoot a full race 308 to test the theory. A 300 mag would be even more interesting.

Wait -- Mike Mohler has already run this test, with a production class rifle. But the lesson has apparently been ignored.

Perhaps the best evidence that large case capacity isn't too much of a handicap is Mike's record, with the 243 win, of almost always beating 90% of the 308s and often beating them all (he won all the marbles at the 2007 nationals and owns several national records).

Mike's performance with the 243 also calls into question the assumption that a competitive cast bullet gun has to be 30 caliber but nobody seems to have noticed that either.

We do seem to have a bit of the herd instinct in us.

John

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JSH posted this 06 February 2010

Very interesting thread. I like these types as it leaves one with a lot of food for thought. I have found there are a lot of variables. You take a top notch shooters gun and ammo, a little bit of coaching to a new shooter. And the results can and usually are excellent. Take the same gun swapped off to another fellow to load and shoot with and his results may be terrible. Loading habits/techniques and shooting ability are wide spread. I have seen a lot of $$$ spent just trying to win bragging rights and never get it done. Just because the person didn't have the ability to do it. I have a gun that was originally chambered in 7Br, then rechambered to 7IHMSA, and now ahve a barrel in 30BR that I am wanting to play with. The 7BR to the 7IHMSA was done prior to me owning it. The &IHMSA is a fine cartridge, but a bit more steam than one needs. I wanted the 30 BR as their are a lot more molds in 30 caliber than most.

To the original question and what you seek. I myself would point you towards the 38-55. Brass is easy to come by and can be made from the ever popular 30-30 if need be. There are a lot of proven moulds out there and it is a proven performer at the distance you are looking at. Bore size is one thing I would really think about. I have looked into this caliber for a long time. .377 or .380.........I am up in the air, but trying to get what you are after, I would paper patch either one. The only thing that has kept me from jumping in and building or buying a 38-55 is I have the itch to shoot to 1000. So the lightest to get there would be the 45-70, but if I were ever able to get to Raton, that one is out to my understanding. And yes just having both has crossed my mind more than once,lol. jeff

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slowshot posted this 06 February 2010

If you could ask Ned Roberts about a 40 rod gun- he would say 38-55 .375 Ballard or Hi-wall (mine was Remington roller with Douglas barrel )smokeless or Black or duplex ,plain base, gascheck ,pistol or rifle primers mine digested any and all and won several well attended off-hand matches @200 yds If you check out a winners list of the current Schuetzen matches you will see 38-55 is by far the choice - they also give all the specs of gun and loads,all that info used to be in back of The Black Powder Cartridge news - enjoy the journey Slowshot

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mlr1m posted this 06 February 2010

The 38-55 looks like a better choice than a 32-40 for me as far as brass availability and wind bucking ability goes. I'm not sure how much of an advantage a 38 would be,if any, over my 40-65 though. With a bullet weighing about 100 grains less I would think its recoil would be much milder.

This all depends on my being able to come up with the funds. For now I have loaded up about 300 rounds of paper patched and greased groove bullets loaded up for my 40-65 an my 45-90 waiting on warmer weather to arrive.

Michael

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209jones posted this 11 February 2010

Check out the ASSRA forum,there is a lot of info in it on 32-40 and 38-55. The top guns in that crowd are mostly 32 cal, they are running as high as 250gr bullets in them now, and getting under 1” ten shot groups out of them. I built a 32-40 on a Browning 1885 that will shoot 1-1/4 on my good days with the 209 Jones bullet and AA #9. I saw under 1” groups shot in Tacoma, 17 yrs ago, with that bullet, out of a gain twist barrel

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Mnshooter posted this 11 February 2010

I would guess that the 30-40 would be a fair bet in a rifle like the Winchester High Wall Copy. You have a long neck and reasonable powder capacity. As it was used in military rifles and the 32-40 was king it may have been overlooked. Also you have a pile of 30 cal molds like the lyman 311284 at 220 grains which was made for it. For unfussy cast cartridges the 30-30 is top for me with the 303 Brit a surprising second whci is very close to a 30-40.

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NITROTRIP posted this 11 February 2010

HI all, I have'nt posted in a while, you know that busy stuff. Nice to be back. On the topic of 38-55, ML Mcphearson just wrote a very extensive article in Precision Shooting a few mounths back. As I recall, it deals with 100+yrs of bullet dia. chamber dia. to brass thickness, to bore miss fit. Bad enough that Starline is now makeing correct brass to correct the problem. And from what I hear from a couple of guy's that cast and have the new brass, they have cut there group size down buy an average of 3times. I don't have the month of the magazine handy, but you can call them and get a back issue. This seems to have raised this cartrage to a whole new level. This is a very good article with a lot of historical backup for the what and why of all this. I am now looking at the baby Sharps in this chambering for all these same reasons. This now could be one of the very best for cast smokeless, or blackpowder paperpatch. Because now the case is the correct length, almost an 1/8 inch longer. Part of this comes from the brass company's makeing the brass from 30-30 base cases for economic reason's. They come out about 1/8 inch short and the necks are to thick. When you get a bullet dia. to fit the bore the case neck dia. is to big and they won't chamber. Plus the short case. Check out the article, as it is a very good read and explaines the problems I had 27yrs ago with Marlin lever. Now I wish I never would have sold it. OH Well.

Rick

PS, Starline has sized the necks to work best with cast bullets.

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7mmxbolt posted this 18 April 2010

As I am a dedicated single shoot enthuesiest, I own two T/C Encore Prohunters. One is dedicated to a T/C barrel in 25-06 “my varmint rifle” and the other sports a new Bergara barrel in 300 WM. The 300 believe this or not is my dedicated Schuet-zen rifle. For those who do not know what that is, it consists of using a SS rifle only, no bolt guns and a lead round to be shot off-hand at 200 yards and a telescope is legal. Anyone who knows Schuet-zen also knows full well that this is definitly not the cartridge of choice. Many feel it is way to large and there are certainly much better choices to choose from. The 32-40 has been the king since before the Civil war along with a few others. Did I choose this cartridge on purpose, absolutly not, it was what I had at the time I got involved so I rolled with it.

Well I have spent some time trying to get this rilfe to be competitive and finaly found a combination that I feel “as long as I do my part” will be. The load consists of Reminington cases which after fire forming are only necked sized. Bullet used is the Lyman # 311332 sized to .311 with a GC and with my alloy after sizing ends up being a 195 gr bullet. Lubed with Carnauba Red and seated at 3.040 off the ojive. Seating this long allows for a good seal in the bore and also insures for the best possible alignment and the bullet then finish seats in the case simular to breech seating but much easier. The use of the 30 long Lyman M-die is essential as I just kiss the mouth of the case enough for the GC to seat inside. Behind 22.0 grains of IMR SR-4759 this load runs at 1612 fps on avg.

The below target was fired from 200 yards, first benched then off hand. The pasties are 10 sighter rounds used to zero the scope. I had adjusted the load by moving the seating depth from where I originally had it to 10ths deeper into the lands. It went from just under a 1 1/4” CTC load to what you see in the X ring which is a 4 shot group. The buck shot looking group or remaining holes is me trying real hard off hand to look good which is not bad seeing it was only the 3rd time out this year. I have been competing in Schuet-zen about a year and use this rifle and a Savage BTVSS 22lr for the rim fire class.

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JSH posted this 20 April 2010

Neat. I have a 330WM that I picked up for a song. The only load combo I have ran through it was SR4759 and the RG-4 bullet. Shot exceptionally well at 100. As big as the case is i am tempted to try some trail boss in it. Mine is the 26” heavy barrel. Stock is the plastic one. I found it for the price of a forearm, I am a wood and blue steel guy myself, but $$ dictated this one. The bore is acting like it is kind of rough from the fouling I get though. A few rounds and some JB's i think will smooth it up.

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TonyT posted this 20 April 2010

I do not bel;ieve that any particular cartridge is inherently more accurate than another. One can chamber a quality single shot action in a wide variety of calibers with outstanding results more dependent on the shooters ability than the cartridge. I have an older Browning high wall in cal 30-06 which will give me 1+ inch groups at 100 yards if I do my part.