boolit shape??

[mikeym1a]

I've been trying to learn more here, but, I don't understand the why's and wherefores of boolit shapes.

A jacketed bullet can have a long, slender shape with minimal bearing surface, and it seems to fly straight. But from what I've been reading, cast boolits seem to need a long tubular shape to fly straight. How come? I've read that they can enter the rifling crooked, and that detracts from their accuracy. Doesn't the same apply to the J-words? Can anyone help me understand this better? Thanks.

[RoyEllis]

Main reason jacketed can successfully use a slender nose is due to the jacket preventing nose slump caused by initial accelleration forces which deforms a cast boolit causing very erratic flight and extreme accuracy loss. There's a lot of other factors as well, but this is a major player in shape design choices.

[Jaak]

Because lead is much softer than copper, when it enters the barrel at an angle it deforms and becomes canted relative to the barrel. When this happen with a copper jacketed bullet the harder copper causes the bullet to "self correct" lessening the effect of the cant. Lead also "self corrects", but only a very small amount. The harder the alloy the better the "self correcting" ability.

The BHS of copper jackets(it is not pure copper; it's called Gilding Metal) is 114, give or take. The hardest you can get a lead bullet, as you probably know, is about 30. And then there are steel jacketed bullets...