Hey guys - I could use some advice. Earlier today at the range I had a failure to fire, and while trying to diagnose the problem I discovered some unusual hits on the primers. At this point I'm wondering if the rifle is safe to use or needs some attention by a professional gunsmith. (Apologies for the crummy pics - couldn't get my camera to focus any closer)
The rifle is a CZ-550 in .30-06, brand new when I bought it with about 300 rounds down the barrel thus far. It has been flawless with no malfunctions of any kind up until this afternoon. After about six or seven shots I got a 'click' on a live round - a factory Federal Premium 165gr Sierra GameKing. The round fed with no problem and extracted easily. On examination I found a dimpled primer, assumed it was a bad primer and tried another round - exact same result. I switched out to another load - factory Remington Core-Lokt 180gr - same result.
Dimpled Primers:
At that point I pulled the bolt out and stripped it, cleaning everything thoroughly. The only thing I noticed was a little bit of dark grimy build-up on the bolt face around the firing pin hole, which wiped off easily. I reassembled and reloaded a fresh round which fed, fired and extracted without a problem.
When I looked at the primer, however, I noticed that it was bulging up around the dimple. I looked at the other cases I'd already fired today and noticed the same bulge on all of them. Both the Fed Prem 165's and the Remington 180's had the same bulging primer around the dimple.
Bulging Primers:
I had no idea what was causing this, and rather than risk any damage to the rifle I quit for the day. When I got home I checked some old brass fired from the same rifle and found standard primer hits on the same brands and weights of ammo.
Standard Primer hits:
I've only shot factory ammo out of this rifle and clean it regularly, so I have a hard time believing its overpressure spikes or fouling in the barrel. The only thing I could think of is a problem with the firing pin. As trigger-control practice I dry-fire this rifle a fair bit (always with a snap-cap in place) and when I measured the pin against one from another CZ-550 (from a .375 H&H) I noticed that it was 11.5mm vs 12mm in length. The 30-06 is on top, the 375 H&H is on the bottom:
Firing pins:
I'm wondering if I've somehow worn down the pin on the .30-06 and that caused the bulging primers, which led to the fouling on the bolt face, which led to the FTF. I'd like to save an unnecessary trip to the gunsmith if possible.
Any thoughts?
The rifle is a CZ-550 in .30-06, brand new when I bought it with about 300 rounds down the barrel thus far. It has been flawless with no malfunctions of any kind up until this afternoon. After about six or seven shots I got a 'click' on a live round - a factory Federal Premium 165gr Sierra GameKing. The round fed with no problem and extracted easily. On examination I found a dimpled primer, assumed it was a bad primer and tried another round - exact same result. I switched out to another load - factory Remington Core-Lokt 180gr - same result.
Dimpled Primers:
At that point I pulled the bolt out and stripped it, cleaning everything thoroughly. The only thing I noticed was a little bit of dark grimy build-up on the bolt face around the firing pin hole, which wiped off easily. I reassembled and reloaded a fresh round which fed, fired and extracted without a problem.
When I looked at the primer, however, I noticed that it was bulging up around the dimple. I looked at the other cases I'd already fired today and noticed the same bulge on all of them. Both the Fed Prem 165's and the Remington 180's had the same bulging primer around the dimple.
Bulging Primers:
I had no idea what was causing this, and rather than risk any damage to the rifle I quit for the day. When I got home I checked some old brass fired from the same rifle and found standard primer hits on the same brands and weights of ammo.
Standard Primer hits:
I've only shot factory ammo out of this rifle and clean it regularly, so I have a hard time believing its overpressure spikes or fouling in the barrel. The only thing I could think of is a problem with the firing pin. As trigger-control practice I dry-fire this rifle a fair bit (always with a snap-cap in place) and when I measured the pin against one from another CZ-550 (from a .375 H&H) I noticed that it was 11.5mm vs 12mm in length. The 30-06 is on top, the 375 H&H is on the bottom:
Firing pins:
I'm wondering if I've somehow worn down the pin on the .30-06 and that caused the bulging primers, which led to the fouling on the bolt face, which led to the FTF. I'd like to save an unnecessary trip to the gunsmith if possible.
Any thoughts?
