Load Development - Brass & Suppressor Questions

[BearNaked]

This post could go into a couple different sections, just figured hear would be best since i am more worried about the brass.

I was doing some load development this weekend for a new AR in 6.5 Grendel and I came across some interesting findings that I have some questions on.

I was shooting unsuppressed and the brass was coming out with a flat spot on the neck from hitting the case deflector too hard, need a heavier buffer and/or stronger spring to fix that. But when I shot suppressed, it was coming out perfectly round and the even weirder part is that brass was flying out at 3:30 every time no matter if it was suppressed or unsuppressed. Usually your brass flies out at 4-5 unsuppressed and at 2-3 suppressed. I asked the guys at the gun shop and they said that the suppressor is giving the gas a different recoil pulse, if that makes sense, with the suppressor on it so it was acting more like a shove instead of a snap which was causing the brass not to hit as hard as it does unsuppressed which is completely backwards from what I have always noticed. usually the brass is being slammed harder backwards with a suppressor on it.

1)I will be annealing after each firing but will the brass be overworked with necks being flattened on one side? I know annealing will help with this but how much damage if any will this cause to the brass?

2) is the brass flying out at the same location suppressed or unsuppressed an issue?

3) What are your thoughts on why this is happening to the case necks when shooting unsuppressed vs suppressed?

Gun Specs:
Sons of Liberty lower/Aero Precision m4e1 upper
18" Ballistic advantage spr barrel with rifle length gas
Seekins adjustable gas block
h2 buffer
blue springco spring

 

[Olen_4504]

without diving into WHY it's happening.

i have the same issue on my bolt action with the brass coming out and smacking the back of the action and denting my case mouth.

so I put a little piece of stick on foam where the brass hits. problem solved.

you could do the same thing on your AR.

 

[BearNaked]

Never thought about doing something like that. I will have to try it.

 

[Supersubes]

I see no issues at all with any of that. The rest of your case will take a hammering and fail long before a regularly annealed neck will. I wouldn’t worry about it.