What would you size them at?

[.429]

I've got a H&R .45-70 (not a buffalo classic) that I need to buy a size die for. I slugged the barrel yesterday, and it came out to .456" with a mic (my calipers showed it to be .4555"). This does appear to be a microgroove barrel, and I hear ppl say on here to run them pretty fat. I've got the NOE 350gr RD PB mold and it's dropping some purdy boolits at .4605". I'm thinking that I should size these about .458" or .459". What do y'all think? Oh yeah, these boolits will probably get powder coated. Thanks for the input.


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[Outpost75]

Do a pound cast of the chamber and origin of rifling.

IGNORE the groove diameter of your barrel!

MEASURE the diameter of the "ball seat" or the unrifled portion of the chamber in front of the case mouth before the rifling starts.

SIZE bullets to not exceed THAT diameter. Probably about .460-.462 for your Buffalo Classic.

I have a .45 Colt Buffalo Classic which likes .458" and .452" bullets of groove diameter keyhole!

[runfiverun]

since they are plain base I would try one- dummy to see how it chambers and such, then go shoot 20 straight from the mold and see what happens.
a little tumble lube would get you up and shooting pretty quickly.