300 Win Mag once-fired case trimming

[Beiruty]

300 Win Mag Spec asks for Case length not exceeding 2.620"
However, my once fired brass was cleaned and primed and I assume that no need for trimming. However, when I checked case length, I was seeing 2.628"-2.636" That is 0.008" to 0.016" over.
Is that okay or should I de-prime and size then prime again?

 

[BLDTYLRY]

I would trim.

 

[ZiaHunter]

That is a fair amount of variation in once fired brass. You may want to check headspace with a comparator before trimming. Was the brass sized after the first firing? Also cases should be trimmed after sizing.

 

[427Cobra]

Get a Chamber Length Gauge from Sinclair, in non Mag calibers trim back .010 from what it reads, I don't know about Magnums first hand but .020 should no problem, and no matter what you think you can't shoot the difference in .010 trim length.

 

[Beiruty]

I am trying to load:
Re-used case: Hurter's Select Hunting rds, once fired in my rifle.
Primer: Win LR Mag
Powder: Alliant Power Pro 4000-MR ( Similar to RL-22?) 70 grs.
Bullet: Hornady .30 Cal 208 gr A-max.

Rifle: Steyr SSG-04 with factory certificate of 0.6 MOA
Purpose: to get 5 rds all touching at 100yrds.

first 10 rds: