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In .45 or .50 what rifling twist and depth will work and a source for 1" across flats barrels thanks for help
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You might try 1-48 for your rifle but this will not handle round balls except with VERY heavy powder charges. The longer the bullet design you choose for your rifle, the faster the twist will need to be to stabilize a minnie.You could even potentially use a hollow base 45-70 bullet at around 1-20 or so. The rule of thumb is minnie designs need to be spun faster than round balls but fast twists won't stabilize a round ball. There is no free lunch. Good luck with the build- IrishFritz
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I have friends with Thompson center 45 caliber rifles, designed to shoot maxie balls and round ball, rifiling is not as deep as for round ball only. They shoot round ball great with 50 grains of 3fff. I had a friend years ago that shot 110 grains of 3fff with Maxie balls very well. I would check to see what Parker Hale rifles used but they are .58 and I understand they try many different moulds to find the minni ball thats works best in thier rifle.
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I have been gathering information on building a slug gun as they call them and "most" of the guys are recommending a 1-18 to 1-20 rate of twist for the 45 cal .458 Dia. barrels that is with a .459-.460 DIa. bullet in the 500-535 grain weight range.
Usually backed by a cardboard over the powder card and a lube wad on top of that and then the bullet.
And 85-100 grains of three FFF powder.
Bullets are either grease groove or paper patch variety.
Last edited by underhammer 1962 (6/21/2018 4:06 PM)