Pressure Signs?

[StoneDog]

Hi Everyone,

I'm trying to work up some loads for my 16" Grendel (264 LBC chamber, actually).

I was using once fired Hornady brassed, full length sized. Loads were built with CCI 450, Nosler 123 CC and 8208 XBR. I was working up from 26 to 28.1 grains in .3 grain increments. At 27.5 and 27.8 I had 3 cartridges (below) that show a mark on the shoulder.

IMG_0257.JPG

The primers are fine, perhaps very mild flattening if at all.

Anyone seen this before?

[cb4017]

That's odd. Never seen that before. It looks to me like a brass shaving or some other debris is in the chamber and being imprinted into the brass on firing. Have you checked the chamber?

[StoneDog]

No, I didn't notice them until I was back home. I shot over 40 rounds at the session and these are the only three that exhibited the "smile".

[cb4017]

Just looks like some debris got into the chamber. It may have already worked itself out. I would just do a good cleaning and carry on.

[LRRPF52]

I've never seen that before either. Really weird.

[StoneDog]

Thanks everyone. I won't stress over it then.

[CCW]

Any cannelures, roll crimps of neck to bullet, or taper crimp to bullet involved? The reason I ask, I have seen an AR-15 generate ringlets of brass sheared off neck ends, when long necks and/or small case head space allowed the cartridge to bottom on the chamber neck relief, instead of the conical section / shoulder contact. What is your trim length after full length sizing?

---CCW

[Rickc]

Lots.of.carbon on those necks.

Almost looks like the neck didn't seal tight to the chamber walls and gasses bled.by into the.shoulder area

[rickOshay]

Looks similar to a brand new .243 WIN case I just found in a pack of 50 from Winchester.

[Klem]

Lots.of.carbon on those necks.

Almost looks like the neck didn't seal tight to the chamber walls and gasses bled.by into the.shoulder area

I'm with rickc on this one. Looks like high pressure gas forcing it way back in one spot as the rest of the neck seals. Like if there is a nick or large scratch in the chamber at the neck.

[rwh]

Did you clean the lube off the case after resizing?