Boolit size with gas check

[historicfirearms]

Ok, I thought I knew lots of stuff about cast boolits, but looks like I've got a rookie question again. Here's the scenario. My 44 magnum revolvers both have .431" groove and .432" throats, so I'm sizing to .432. I just got a Lee 430-310-RF mold that drops at .430". I ran some through the Star he other day and installed gas checks with the .432 sizer. They shot good groups in one of my guns, and no leading in either.

How critical is boolit diameter with a gas check that's sized properly? It is mostly a theoretical question, because I lapped out the mold to drop .432. Just curious if others have experience with a small boolit and proper gas check diameter.

[Iowa Fox]

I'm doing the same thing with a Lee 430-310. I think lapped out to 432 or 433 will guide the bullet into the throat better for me on my single shot. I say this because I have a LBT LFN that drops at .4345 and the fatter bullets shoot much better. I just don't shoot that many of the heavy weights from this Lee mold but I'm just about ready to lap mine. Care to share the details of how you lapped your mold?Did you lap the gas check shank?

[fredj338]

I have found the bullet dia/fit w/ a gc is less important then a naked lead bullet. I would still beagle the nold & get it to cast larger. Then you may have issues seating a gc as the band will be slightly larger. I never figured out why that bullet has a gc anyway. You aren't going to drive it much faster than 1300fps, but it does allow you to use a softer alloy.