Are you shooting these in some type of short 30, ie, 30BR, 30PPC, etc?
Wouldn't it be easier to send the barrels back to the Gunsmith and have him set them back using a "zero" freebore reamer?
I have shot 8 Ogive 118 grn bullets built on 1.000 length jackets, and you just about need a zero freebore, as they stick further out than a 112 grn built on .925 jackets.
I guess my question is, did you want a longer freebore?