Choosing the mould "size"???

[DakotaElkSlayer]

Been searching, but can't find the answer... Ok, my 32H&R Mag likes .312 bullets and want to cast bullets to that size. If I buy a mould that is supposed to be .312, will I be safe or will some alloys cast smaller? Looking to buy my first mould and would love to hear some input.

Thanks,

Jim

[Dale53]

I prefer to have my moulds cast slightly larger (as measured with an alloy of WW's+2% tin). That gives me some leeway for alloy caused variabiles in diameter.

I have a number of .32 H&R magnums (S&W & Ruger) and mine are happy with .313" bullets. I want my moulds "as cast" diameter to be .314".

Dale53

[Wayne Smith]

If you buy from any of our moldmakers here on this site you will have either 1) a boolit that is exactly the size you want in the reference alloy, or 2) a mold maker who fixes the mold the first time! A boolit mold you design on Dan's Mountain Mold website will be the same.

Results from any of the mass producers will be more spotty.

[mdi]

To get a mold that casts the same size as the manufacturer (the big guys, not custom or semi-custom mold makers) you'll have to know the exact alloy they used, what temp the alloy was, and mold temp. They, the manufacturers, determine the size/weight and may make a few molds for testing, but then they go to mass production where the variables grow...

[Bret4207]

No, the chances of getting an as cast boolit that is exactly the size you expect is between slim and none. BUT! You can alter your alloy to increase as cast size, lap the mould, beagle the mould, have the mould opened. The safer way to do things is to spec you mould to drop "fat" and size down or shoot it as cast. For .312 I'd ask for something of .313-14. Another way to do it is to provide samples of your alloy so the maker can figure your shrinkage. This is with the custom guys. With an off the shelf it's a total krap shoot.