300 H&H brass..what's best for 1st load?

[thepitchedlink]

Morning gents, I'm putting together the bits to build myself a 300H&H. I've tinkered with belted mags a bit, but not a H&H. I'm just wondering about how to prep the brass for the first firings. I'm wondering about either fireforming with a light charge first to blow the shoulder out gently, or, opening the neck up to .33, then neck back down to .300 and see if I can create a false shoulder. Any thoughts? I'm wondering how the false shoulder will work on a case that doesn't have much of one to begin with

 

[rgv]

if you are starting from scratch, have it headspaced it under saami spec.

the go/no-go on belted mags is .220/.226 IIRC, and almost all current production brass runs anywhere from .213 to .216.

If headspaced in the 220/226 range, you will fight casehead separations with either the 300 or 375 H&H.

if you headspace it so it will just close on the longest belt you can find, then you will get decent case life.

Obviously, you have to be prepared to have a case not chamber, run your cases through the gun before you go hunting.

 

[rnbra-shooter]

Shouldn't the belt provide all the location that the case needs?

Myself, I'd load the new brass with ordinary loads and go (that's what is done with factory ammo after all! ;-)

 

[rgv]

Shouldn't the belt provide all the location that the case needs?

yes, and on the first firing of a modern belted mag (7 rem mag, 300 win mag etc), the shoulder will blow forward, and you can then set your dies to not bump the shoulder back, and you no longer rely on the belt for headspacing.

on the 300 and 375 H&H, with their very shallow neck angles, that doesn;t work, and you will get casehead separations far sooner than you will with regular bottleneck cases with correctly set dies