bore size bullet

[Hank45]

I want to breech-seat a bore size bullet (.277) will it expand the base enough to fill the groove diameter of the rifiling (.286) I will be using black powder? Hank

[stubshaft]

BP will bump up a soft lead projectile, but I don't think it will bump it up that much. The old timers like Pope used boolits of the proper diameter when breech seating.

[runfiverun]

actually Dr. Mann used bore diameter boolits of pure lead and fast [thats all they really had] rifle powders as well as black.
dr mann wrote a very good book on the subject.
it's on google books or something like that it might even be in castpics.