Measuring throats jacketed vs cast

[David LaPell]

I used the old way of measuring my cylinder throats with my Vaquero (has always worked in the past) and I used a .451 FMJ. The bullet seems a pretty good fit with these, but how do these compare to lead SWC's? I am going to dig around later and see if I have any .45 Colt lead loads around but I think I have used them all. How do jacketed bullets compare with lead since I don't really load alot of jacketed vs lead?

[Wayne Smith]

I have no idea what you are asking. A hole is a hole, once you know the size of the hole it matters not what material goes through it, it is still the same size.

[303Guy]

True, but is the boolit size requirement the same?

[David LaPell]

I guess what I should have put in the question is because sometimes you see a lead bullet diameter listed as one size for the same caliber and the jacketed another size, is it the same thing when sizing cylinder throats? I have seen some loading guides list even with the .45 Colt as jacketed bullets as .451-.452 and cast as .454. Why the difference in size?

[303Guy]

For rifles, and I would assume the same applies to pistols, throat fit is important to align the boolit as well as to seal the bore so oversize cast boolits would be desireable if not necessary to prevent flame cutting and leading.

[mooman76]

Jacketed bullets are more forgiving as compared to lead when it comes to size. If jacketed is slightly undersized, no big deal but with lead you get leading.