Gas leaking from primer pocket

[Dos Perros]

Been reading for a while, first post after I didn't find what I was looking for in the search feature.

I went to the range for the first time with a factory new Sako A7 in .25-06. I tried three different loads, all with powder charges near the minimum in the Sierra manual. I am seeing burnt powder residue around the primer on most cases. No other apparent signs of high pressure (no ejector marks on cases, no stuck bolts, no flattened primers, nada).

I'm suspecting crappy brass. I'm using Winchester .30-06 new brass necked down to .25-06 with CCI BR#2 primers. Here are some pictures for reference.

One of the very worst ones.

Here's a look at the bolt face. New Sako A7 on the left, Tikka T3 with ~1000 rounds through it on the right.

I have some Lapua brass on order so I'll have a comparison soon. Also, I did shoot some Remington box ammo to get the scope dialed in and for potential warranty issues.

Thoughts? Thanks for your input.

 

[Paladin2147]

Re: Gas leaking from primer pocket

At near minimum, you are likely running too little pressure. The BR-2 has a harder cup. What is the load chronoing at?

 

[aam]

Re: Gas leaking from primer pocket

What kolkio said.
What I think is happening, because of the minimum charge weight, the primer is coming out of the case head, allowing the gasses to escape before the case head has time to slam against the face of the bolt.

I think the brass is fine. Very rarely do you get crappy brass.
If you were to increase your powder charge gradually, you will find this problem to go away.

CAUTION.. Work up loads carefully looking for signs of pressure.

 

[dbateman]

Re: Gas leaking from primer pocket

Yeah another one for your load not being hot enough.

 

[MitchAlsup]

Re: Gas leaking from primer pocket

Agree with the above, with the caveat that the shoulders may have been pushed back too far--which exasterbates the leakage problem.

Primers looks just fine, I would bet the necks have soot on them as well.

 

[Dos Perros]

Re: Gas leaking from primer pocket

I've compared the once-fired cases to the unfired cases and, depending on the case, between 2 and 3 thousandths of difference in length of the shoulder measured using the Hornaday headspace system. I only neck-sized the new .30-06 brass because, after trimming, the cases fit just fine in the gun. I figured I wouldn't mess with anything I didn't have to.