I have an H&R Buffalo Classic in 45-70. It looks like it has shallow groove rifling, and I haven't found a cast bullet it likes yet. Has anyone else experienced this? I've tried ww, ure lead, and a mixture of both. Would a gas check boolit be a better try? Any cast/powder combos you can recommend?
Cast bullets in a microgroove barrel
- Thread starter Papaclaude
- Start date
I have a Marlin 44 Mag with microgroove rifling. It shoots marvelously with .429 cast wheel weights. Different lubes will make a lot of difference IMHO. Lyman Alox bullet lube works best for me.
Rechecked my sizing die for 44. It is .430 not .429
Rechecked my sizing die for 44. It is .430 not .429
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The bullet needs to be minimum of two thou larger diameter than the groove diameter of the barrel for best results. Three thou may be even better.
Marlin micro-groove diameters are usually oversize, .3095" in the grooves for 30-30 is common, so the bullet needs to be at least .310 diameter. The trick is to get a bullet seated in the case that is large enough to fill the grooves in tghe barrel, and will still allow the case to chamber with the larger neck diameter of the loaded case.
Also, you must get all the copper fouling out of the barrel for best results with micro-groove barrels. Sweets 7.62 or plain old household ammonia is your friend.
You will only know by trying.
Ted
Marlin micro-groove diameters are usually oversize, .3095" in the grooves for 30-30 is common, so the bullet needs to be at least .310 diameter. The trick is to get a bullet seated in the case that is large enough to fill the grooves in tghe barrel, and will still allow the case to chamber with the larger neck diameter of the loaded case.
Also, you must get all the copper fouling out of the barrel for best results with micro-groove barrels. Sweets 7.62 or plain old household ammonia is your friend.
You will only know by trying.
Ted
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back40sniper
CGN Regular
- Location
- South east Sask.
Have a lever in 41 Mag with micro groove, just need to increase bullet diameter as mentioned. There is a definite sweet spot.
I was powder coating. Will try the Alox, though. I'll mike my boolits to see what the diameter is.
Hard cast refer to the alloy hardness not coating of some sort.
My experience with a 1894 Marlin in 44 Spl/Mag, bore/grooves are generous. H&R is not microgroove, the groove may look shallow but they are probably "normal" SAAMI (.450/.456). That H&R was made for cast. Are you using Black Powder?
No experience with 45-70, but COWW is app 12.5 BHN, not hard by todays standards. Lino is 22 BHN. Most commercial cast is 92-6-2 and around 15.
A gas check does work. Things do not need to be as "right" as for plain cast.
An easy experiment is to heat treat the bullets you have, make sure it is COWW only, no lead, no stick on WW.
More details would help, as you may have an obvious issue. Powders make a difference, velocity makes a difference, bullet weight makes a difference.
5744, 4198, 4759 are my go to powders for cast in 38-55 and others. 1400 to 1600 fps is a good velocity for soft(ish) cast. You didn't indicate any leading issues, so I'll assume that the lube you're using is good and your velocity is in the zone. If it were my rifle I'd start with a 405 gr cast @ 15 BHN, with SR4759 or 5744, with Trap Door data.
Search for BPCR if black powder is your thing. Your best help may come from other forums. H&R made lots of the BC, and 45-70 has lots of followers.
Came close to buying one of those Buffalo guns, on more than one occasion, especially when they were clearing them out in the end.
Your gun has not a microgrove barrel. Only Marlin used this type of rifling.
The first thing you have to do with any barrel you want to shoot cast bullet in is to slug the barrel and do a chamber cast. This will give you the throat diameter and barrel dimensions. From there - you must have a bullet mold that is trowing bullet big enough to allow-sizing to proper diameter or just used as cast AND a bullet style that fit the throat. You also want to find out your max oal with that bullet - just touching the rifling.
Alloy : depend on what velocity you are looking for. WW - clip on are good in the 1100-1400 fps range. Faster they have to heat treated them that will allow up to 2000 fps with a gas check.
You have also to consider the quality of bullet casted: are you weight sorting them to +- 1 grains ? For match I use +- .5 grains.
Lead bullet properly fitted to a barrel - proper alloy - proper lube and powder for the speed range will do it. One other factor to consider is your barrel twist.
1/18 shoot heavy bullet 405-500 grains + very well. 300-350 most gun don’t like them with that twist, but this is not written in stone.
There is a reason why you gun is not shooting lead bullet as tight as jacketed. I own and shoot 3 45/70, a 30-30 and a .45 colt and all outperform jacketed bullet for target work.
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Gas check won't make too much difference if any below 1500-1600 fps in most rifles and gas checked bullets still need to fit the bore properly. Poor fitting checked bullets won't work any better than poor fitting non-checked bullets.
Bullet fit is the biggest cause of poor accuracy with cast bullets. For accuracy the cast bullet needs to seal the bore, to prevent gas cutting of the bullet. If the bullet doesn't seal the bore, the burning gases jet past the bullet melting lead as it goes. Result is a bullet that may be unbalanced and leading in the bore. That's not so much of a problem on jacketed bullets.
The 2nd biggest cause of poor accuracy is bore condition. If there is jacket bullet fouling in the bore, it will rip chunks of the cast bullet off as it goes past and the result is an unbalanced bullet and a leaded-up bore. Neither makes for accuracy. If a rifle has been used with jacketed bullets give it a good scrub with lead and copper remover before starting with cast. Doing so will pay dividends in accuracy and the barrel will not foul nearly as quickly if at all.
Bullet fit is the biggest cause of poor accuracy with cast bullets. For accuracy the cast bullet needs to seal the bore, to prevent gas cutting of the bullet. If the bullet doesn't seal the bore, the burning gases jet past the bullet melting lead as it goes. Result is a bullet that may be unbalanced and leading in the bore. That's not so much of a problem on jacketed bullets.
The 2nd biggest cause of poor accuracy is bore condition. If there is jacket bullet fouling in the bore, it will rip chunks of the cast bullet off as it goes past and the result is an unbalanced bullet and a leaded-up bore. Neither makes for accuracy. If a rifle has been used with jacketed bullets give it a good scrub with lead and copper remover before starting with cast. Doing so will pay dividends in accuracy and the barrel will not foul nearly as quickly if at all.
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I'll get some ammonia just to make sure, but the bore seemed pretty good. I've been powder coating, which also bumps up the diameter by a few thou. Is this OK?
I hope you have better luck with Alox. Worth a try.
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Johnn Peterson
CGN Ultra frequent flyer
- Location
- Chemainus B.C.
Much of my 'need' to get into casting was to, inexpensively as possible,
fill my bullet supply requirements for competition handgun 'paper punching'. A fairly hard and consistent lead mix I relied heavily on was wheel weights. In the larger handgun calibres such as 357 - 45, I'd go for 0.001" - 0.003" over bore diameter. Using a preferred and harder mix for my 'premium' bullets, linotype was my go to choice. With linotype, size for size served me well. For what little in the way of cast bullets I've used in Marlins with microgrove rifling of/in larger calibres, much the same rule of thumb applies.
fill my bullet supply requirements for competition handgun 'paper punching'. A fairly hard and consistent lead mix I relied heavily on was wheel weights. In the larger handgun calibres such as 357 - 45, I'd go for 0.001" - 0.003" over bore diameter. Using a preferred and harder mix for my 'premium' bullets, linotype was my go to choice. With linotype, size for size served me well. For what little in the way of cast bullets I've used in Marlins with microgrove rifling of/in larger calibres, much the same rule of thumb applies.
