How big is too big?

[Philbert]

I have an older (1977) NMBH that has .454 throats and .450 bore. From what I've read this is a pretty large delta. Should I be shooting .452 or .454 bullets (or maybe .453)? What about hardness? I am shooting primarily cast bullets. I have been using 255gr WFN LBTs without leading but then again I never put more than 30-40 rounds through in any given shooting session.

I would appreciate any comments from you more knowledgable reloaders/shooters.

Phil

[largom]

If they fit the chamber shoot them and check results. I only resize if necessary to fit chamber. I shoot .312 Dia. in .308 bores and .460 Dia. in .457 bores all of the time.

Larry

[Wayne Smith]

Let Dr. Gun tell you. Load each diameter, shoot for accuracy, and check for leading. You will quickly find out which you want. My .357 Smiths want a .358" boolit, loads tight but shoots accurately without leading. Load .357 and it loads easier (speed loader) and no leading but not as accurate. I never bothered to measure them, they are both the same.

[XWrench3]

yep, i dont think there is a better way. my marlin 1895 like .460" sized boolits. it has a .4585" bore. my marlin (glenfield) 30-30 requires .311 boolits for a .308" (microgroove) bore. testing is the best teacher. since increasing the size of boolits in each of these, i can count on half a hand how many times i have had the chore boy out, and those were on very fast loads with what i believe was inadequet lubrication.

[Philbert]

Thanks for the replies. Off to the range.......

Phil

[Bret4207]

Is your BORE .450 or is your GROOVE diameter .450?