Problem with my Cooper

[Mike]

I was shooting my Cooper on Sunday and had a "first" happen to me. Toward the end of my session, I was shooting some factory Hornady 40gr loads. When I fired one round, I felt some blow-back hit my right cheek, just below my shooting glasses. The round extracted normally, but the primer had a hole in it. I did a visual inspection of the rest of the case and the rifle and found nothing out of the ordinary. I put in another round and squeezed the trigger. Click. I opened and closed the bolt to try again. Click. I extracted the round and looked at the primer. There was a dimple from the firing pin, but apparently not enough to set the primer off. I tried a second round to verify that it wasn't the ammo and got the same results.

I speculate that the blown primer sent some junk into the firing pin hole and is possibly obstructing the firing pin's path. Before I start doing anything, I wanted to consult with the experts here and see if anyone else has had a similar experience?

[Keith in Ga]

I've got two .204 Coopers, and haven't had a problem of any kind. I would call Cooper and ask them for advise.

[Mike]

Keith, I'm certain that the problem isn't a result of the gun. It's a result of the blown primer.

Have you ever disassembled the bolt on either of your Coopers? That would likley be my next step, but I've never done it before.

[futuretrades]

had that happen to me with my vangard. if the primer is pierced, chances are that there is some of the primer inside the bolt. on my rifle, the result was not able to fire the next round. acted just like the safety was on. had to disasemble the bolt and get all the debrie out of the inside of the bolt. took some carb cleaner with a nozle on the can and under pressure the debrie came loose . i am not familiar with the bolt assembly on your cooper, but you should be able to dis asemble the bolt with a little patience. usually the firing pin is under pressure from the heavy firing pin spring.

[Rick in Oregon]

Mike: I agree with futuretrades, as you most certainly have primer pieces inside your bolt. I had the same thing happen with a M700 in 22-250 years ago, and found tiny pieces of primer inhibiting normal bolt/firing pin operation. Once the crud was removed from the bolts interior, problem was solved.

Give Cooper a call anyway, as it appears they really have good customer service from what I've been told, and if you are unfamiliar with their bolt disassembly, they'll probably walk you through it instead of returning the bolt or entire rifle to them.

[Mike]

Thanks guys! I'll give the folks at Cooper a call.

[jo191145]

We might also concern ourselves with why a factory Hornady round blanked a primer Not good.

[Mike]

We might also concern ourselves with why a factory Hornady round blanked a primer Not good.

I was quite surprised when this happened. I've used a lot of Hornady factory ammo and have never had this problem before. I assume that my problem is debris related (like we've discussed here), and can be fixed with a good cleaning of the bolt. If it's more major than that, I will contact Hornady and let them know about the problem.

[jo191145]

Chicken or egg?

We're supposing the misfires are caused by primer debris in the bolt. Quite possible.
That still leaves the first blown primer to wonder about.
First normal quess is a carbon ring developing that skyrocket pressures.

Personally I'm wondering if the primer shortage has hit the manufacturers and Hornady has switched primers to something less stout. Just a crazy thought.

[Mike]

I don't suspect a carbon ring. I was testing a few different hand loads along with a box of factory Hornady as my "control" group since I knew how they normally performed in my rifle. In this case, the box of Hornady performed worse than I have ever seen. Normally, my gun would stack the 40 gr Hornady rounds into very tight groups. This time around, groups seemed to average almost an inch. That's absolutely terrible for this gun/ammo combination!

It's worth noting that the hand loads were easily making 1/4" or better groups when I did my part. For that reason, I don't suspect anything funny going on inside of the barrel.