Sizing issues

[1shot]

But you said fired was 1.194". This doesn't jive with your 1.1855. It also doesn't jive with the SAAMI minimum headspace of 1.1901" If you size to 1.855 you will grow the case about .009" on each firing. I don't know if the chamber is 1.194 or not but it's probably slightly longer. You will be sizing for a quick case separation. You are probably dealing with the diameter issues others are mentioning and it is probably at the 0.200" line or slightly above.

EDIT: If this brass was shot in a AR you should not use it in a bolt gun unless you use the small base die to resize it. I'm betting it was.

Apologies to @dellet for duplicating his info!

The brass is virgin Peterson brass in my bolt rifle. I use Starline in my AR so I don’t get them mixed up.

 

[dellet]

But you said fired was 1.194". This doesn't jive with your 1.1855. It also doesn't jive with the SAAMI minimum headspace of 1.1901" If you size to 1.855 you will grow the case about .009" on each firing. I don't know if the chamber is 1.194 or not but it's probably slightly longer. You will be sizing for a quick case separation. You are probably dealing with the diameter issues others are mentioning and it is probably at the 0.200" line or slightly above.

EDIT: If this brass was shot in a AR you should not use it in a bolt gun unless you use the small base die to resize it. I'm betting it was.

Apologies to @dellet for duplicating his info!

Never hurts to say it twice, or a different way. Sometimes it helps.

 

[Doom]

The brass is virgin Peterson brass in my bolt rifle. I use Starline in my AR so I don’t get them mixed up.

If this is the case and if the issue is near the base of the case then I have to suspect that you are pushing some high pressure to get enough base expansion to create an issue.

From what I think I know the 6 ARC was developed from the 6.5 Grendel with minor variation to the case and the Grendel was a 52KSI cartridge and the 6ARC is also a 52KSI SAAMI cartridge. Hornady has stated that it is acceptable in a bolt gun at 62KSI but I don't know if the brass is really made for that service.

 

[1shot]

If this is the case and if the issue is near the base of the case then I have to suspect that you are pushing some high pressure to get enough base expansion to create an issue.

From what I think I know the 6 ARC was developed from the 6.5 Grendel with minor variation to the case and the Grendel was a 52KSI cartridge and the 6ARC is also a 52KSI SAAMI cartridge. Hornady has stated that it is acceptable in a bolt gun at 62KSI but I don't know if the brass is really made for that service.

I currently have 7 firings on 1 piece of brass and the primer pocket is as snug as an unfired piece. None of the loads are over Hornady or Sierra’s manual. Primers are not flat with no cratering so I think I’m ok with pressure.

 

[1shot]

I have a T-7, not much deflection but it is there.

I measured the deflection of my T7 with my dial indicator on a magnetic stand attached to the press. When the turret is locked down tight I got .0015 deflection. However when loosening the center bolt just enough to allow the turret to index between stations, I got .0025.
I hope this helps,

Lloyd