Light Primer Strikes - No big deal, only happening to my defender!

[fishhunt]

On a trip last year, we were shoot 12 ga two shotguns with the same ammo. One of the shotguns fired all the rounds, the other shotgun (Mossberg 500) misfired several rounds on and off, e.g. load 5 and 3 misfire. For the misfires, the he rounds had an indication that the primer was struck. After searching online, if seems the shotgun had light primer strikes. I've had this shotgun for 6 years, and fire approx 20 rounds through it per year. Since it's a defender, it would be nice for it to have the ability to actually defend. Has anyone ever experienced this with a shotgun and been able to correct it? Can't determine if this is a fixable issue (something I can fix, something a gunsmith should fix, or if I should just buy another shotgun).

[TimberPig]

When did you last strip it down and clean out the bolt, firing pin and all? Sounds like gummed up oil slowing down the firing pin’s strike. Strip it, clean it out and your issues may well go away.

[fishhunt]

I haven't stripped it completely for 2 years. I guess I got complacent since I haven't been using it much. I will strip it completely and test. Thanks.

[Gateholio]

It is likely a sticky firing pin, as noted.

If you fired 5000 rounds per year it wouldn't be an issue. :)

[net sync]

I've had something similar happen on a shotgun during a range visit after firing at least 50 rounds after I had changed the lubricant I was using on that firearm. I don't recall if the primers were actually getting struck or not, but after firing at least 50 rounds I pulled the trigger a few times and the firearm didn't fire. To make a long story short I switched back to the prior lubricant and had no further issues.

At home I cleaned and re lubed the firearm with the new lube, took the bolt assembly out of the firearm and believe I was able to replicate the underlying issue a few times (a moving part of the bolt assembly was occasionally binding.) I re cleaned and re lubed the firearm with old lube and was unable to replicate the problem either by moving the parts of the bolt assembly or during live fire during subsequent range visits. After firing at least 100 rounds without issue I considered the issue solved. My suspicion is the proprietary corrosion resistant finish on many parts of the shotgun (including certain bolt components) and the new lubricant may not have been playing well together for some reason, or maybe I wasn't properly using the new lubricant, or who knows (:
At this point I can live with the very minor issue of not being able to use the same lubricant for all my firearms. I do however check that the relevant parts of the bolt assembly are freely moving before reassembling the shotgun after cleaning and lubing.

Good luck.

[Redthies]

Another cause may be brand of ammunition. My Mossberg 930 seems to be fickle with Winchester ammo. Some of it results in about a 5-10% misfire rate. I bought a bunch of Kent this spring and come waterfowl season will test it liberally. (That’s the only thing aside from drink that I do “liberally”).

[fishhunt]

Thanks everyone. Appreciate the comments/suggestions. I'm hoping a very thorough cleaning will fix the issue.