Dimpled brass

[Okdeerman]

Anyone have an idea why this is happening. It shows no sign of excess pressure. I chrony every shot and this one was about 30 fps slower. This is a 6.5-06. The brass was made by sizing 270 brass down and trimming excess length.

 

[WAMBO]

Possibly pressure is too low.
Neck not sealing and letting pressure escape pushing that area of the shoulder in.

 

[Frog4aday]

As @WAMBO said, you are TOO LOW in pressure so case neck is not sealing, leading to gas blow-by causing the dimbles. Up your powder charge until dimples go away.

 

[eshell]

Agreed: Pressure too low or powder too slow.

 

[Okdeerman]

I am using 53.5 grains of iMR 4350. My velocity does not vary much. Running usually +or- 10 to 15 fps at 3210. The accuracy is real good. I might try 1/2 to 1 g higher. The higher the velocity the flatter the trajectory.

 

[Tiny Tim]

Possibly pressure is too low.
Neck not sealing and letting pressure escape pushing that area of the shoulder in.

If this were the case, wouldn't there be soot in/near the dimple?

 

[Okdeerman]

There is blackening on the neck. Thanks for your info guys, I will probably bring the charge up a grain and use the same powder since I have plenty of that powder.

 

[WAMBO]

If this were the case, wouldn't there be soot in/near the dimple?

I don't know, maybe, maybe not.

I'm curious as what bullet amd weight he was using?

 

[Okdeerman]

Hey Wambo, the bullet is a 123g Hornady SST. The barrel is a 26in McGowen Precision, 1in 8 twist. Recoil is easily manageable, I love it. This is my 3rd McGowen barrel and they have all been more than acceptable in accuracy.

 

[K.E.C.]

As mentioned above, this is a sign of Low
Pressure, and possibly lite neck tension.