slugging the bore

[krallstar]

I had some time today and slugged both my enfield #4 mk2 and my mosin 91/30 Got some interesting results. First my enfield, when i measure a fired case to check neck it reads .315 So i slugged the bore using a soft lead slug diameter was .320 Slug comes out at .312.5 So that seems good as i can probably use a lead .315 boolit. Now my mosin, case neck expands to .312 but the slug shows .315 Is this going to be a problem.

[Tatume]

Are you trying to measure inside neck diameter of fired cases using a caliper? Get a micrometer, then do this:

http://castboolits.gunloads.com/showthread.php?218414-FYI-This-is-how-I-do-a-pound-cast