7saum case neck size

[saum2]

For those of you using the 7saum, what neck size are you using?
I have Norma 300saum cases that I will size down using FL bushing dies. Probably 2 steps. Then neck turn, but just wondering what neck size you finish up at? .310 or.305?? or does it depend on the reamer?
thanks
Geoff

[bartman007]

Hello Geoff,

Welcome to the SAUM bandwagon.

In regard to any case, the neck OD is dependent on the reamer dimensions.

i.e if you have a no neck turn reamer (stock standard), then you don't turn the brass otherwise you'll have too much clearance and you'll experience carbon burning back on the outside of the neck, even down to the shoulder. And more importantly over work your brass.

A number of people work with varying clearances for the neck to bore, personally I run 3 to 4 thou clearance over the diameter.

I have experienced issues with tight fitting cases in the past due to not enough clearance. When you get up around 20 to 30 rounds after a clean, the carbon builds up on the neck of the chamber, which I feel reduces the 3 to 4 thou clearance somewhat.

If you run 2 thou clearance you may find this clearance after 20 rounds down the barrel too tight, giving you the odd stray shot. You will feel it when chambering rounds, as they will get tight to close the bolt on.

Enjoy the new toy

[BATattack]

Yeah it depends a entirely on your reamer. The 7saum is a lot thicker in the neck than a .284.

I was messing around with the same last night and loaded round with un turned brass was about .316 when forming from 300saum brass.

Ive got a turn neck reamer and its .317 neck. Its up to you but I have thought about making a reamer with say a .312 turn neck so you can use the same/ more avaliable size bushes that people use in their ..284s