Gas blowback around primer?

[staylo]

My father-in-law gave me his Winchester Model 70 30-06 and I took it to sight it in today. It's the first time I've shot it. I put 14 rounds through it and it shot fine, but on the last round I had a puff of smoke blow back around the bolt. When I ejected the casing there are two distinct holes around the primer. I've never had this happen on any of my guns before. Is this something I should be worried about? The ammo is Remington Express Core-Lokt.

[raxar]

could just have been an issue with that round, but I would have a smith check the headspace before I shot it again.

[tl_3237]

I've seen this happen with defective primers - usually with hairline cracks caused in the manufacturing process. When fired they rupture within the primer pocket resulting in a backward escaping gas jet and blackening of the case head as you depicted. You might see some gas erosion pitting on your bolt face from this.

As suggested - doesn't hurt to check headspace. If it checks out, I'd contact ammo manufacturer (assuming not reloads). The casing can be sent to them regular USPS if they so request.

[Hawk]

From the pictures the other cases look fine. I don't see any flattening of the primers which would indicate over pressure or incorrect head space. Now the bad case does appear to have a flattened primer which may indicate over pressure on that one round. I'd have to see at least one additional round (following the bad one) to confirm that it was just one bad round, or something is wrong with your rifle.

[staylo]

Thanks for the replies. All the other Rem cases, as well as two Hornady American Whitetail rounds, were fine before the last one that I had the issue with. I was thinking about having the gun looked at anyway just because it's new to me, but a fairly old gun, so this just confirms that I should have it looked at. Better safe than sorry!

[Arrdy]

Let Remington know about it. Include the lot number with your notification.