View Full Version : Mossy hammerless bolt 22 firing pin break

July 18, 2008, 03:32 AM
I am presently looking at a Mossberg hammerless bolt action 320k single shot 22 for sale at a used gun store. I am cautious because I once owned a Revelation/Savage/Mossberg singleshot 22 of the same action as the Mossberg 320 and the firing pin broke almost on every other shot made. What a lemon that gun was! It became modified to unfireable condition and donated to a HS drama teacher for a prop. Before getting rid of the gun I had inquired about the problem with a friend who examined the rifle.This person told me that it could be that the movement of the firing pin can't handle the heavy slam of the hammer behind the bolt. In order to move the firing pin forward, most or all other bolt actions use a spring moving paralel to the pin, the springs laways being coiled around the same axis as the bolt. The hammerless bolt 22s use a heavy internal hammer to strike the back of the bolt and hit the pin. This guy claimed not to be a firearms expert but he figured that because the bolt assembly was somewhat loose on lockup, their was a lot of play as the hammer hit, tweaking the pin while forcing it forward, and therefore the pin couldn't handle the strain and snaped. It was a long piece of metal that slid out of the chamber when I opened it. I would get it replaced and it would happen again and again! I am hoping that the 320k actually may have a different style , more in-line type hammer rather than what that old revelation 100 had.

I see the reasoning behind the hammer being too much force breaking the pin, but auto-loading rifles and shotguns use the same hammer striking the rear of the bolt, and I haven't heard of constant firing pin breaks with these weapons. Maybe the pins are stouter on these auto loading shotguns and 22s. Could my issues with the revelation model I had be only a problem with the one rifle, or is this a common problem with these hammerless boltgun 22s? Also, are these a regression away from standard bolt action accuracy? I only ask because they definately don't lock up as tight as the standard coil spring stiker fired bolt action. They are like taking a semi-auto 22 design like a 1022, and making it a maunaly operated gun. My feeling on these guns as far as the firing break, is similar to my friends. The standard 1022 type semiauto has a bolt that moves back and fourth but it does not rotate. I feel that since the bolts don't rotate, the internals like the firing pin and extractor are fitted tighter inside the bolt. Since the hammerless bolt needs to manualy rotate to operate the action, the extractor and maybe also the firing pin as well is losely fitted in the bolt. I see it flexing as it is being hit by the hammer and pushed forward thereby breaking.

I am not eager to buy this mossy gun because I feel the pin problem is truly very endemic to the type. As for the accuracy issue, I think these guns can be accurized just as easily as a 1022 can be accurized, though I may be wrong on this also. If the barrel doesn't have a lot of support, it may be problematic. I would like comments on these guns and would like to especially hear from those who may have had the same issues with theirs.

July 22, 2008, 02:06 AM
Delete embaressing thread please

Harry Bonar
July 22, 2008, 03:20 PM
I've been a constant user of Mossberg rifles my entire life. For my money they give you more for the money than any other brand.
I've owned the type you're talking about and I've never had firing pin trouble on a Mossberg. It may be that this partuicular rifle does break firing pins but I'd be suprised.
I'd investigate further. I had a 22 magnum "chuckster" in Mossberg and it was O.K.
I've got several of the models you speak of and no trouble.
Is it possible someone installed a home-made one?
Harry B.

July 22, 2008, 10:03 PM
Thanks for your post. I now realise that the 320K and 346 models and others all are quite a bit different than the Revelation model I had. The revelation model and the similar Savage/Stevens models had a much shorter reciever than most of the Mossbergs. The only think common to them all is that they are termed hammerless bolt actions. I am still interested in the 320k single shot if I can finde one. Very hard to find right now though. The one I saw at the gunshop was picked up before I could decide on it. I did find one other person on a site listing that he had a (342?) carbine with pull-down front grip that he constantly had pin breaks on. I also found a website that listed the firing pins used. What amazed me is that many of Mossberg's hammerless bolt 22s used diefferent firing pins. Some of the guns had a pin similar to that found in my revelation in that they had a small narrow part at the front for the end that strikes the rim. These were early models and later model pins were a flat blade front for the striker. My guess now is that the pin break problem was not as common as I thought. And it may have less to do with the old narrow pin being weak by design, but that the problem was compounded with possibly week metal in the pins and the pins may have not been fitted right.
So I'm willing to give the 320k a try. I see a 320 boyscout single shot on GunsAmerica and may choose this if I can't find the 320k.

July 22, 2008, 10:11 PM
As for the homemade pin, It was not a homemade pin. An the replacement pins I got for it broke as well. I was actually thinking about putting a "homemade" pin in as I was sick of getting new pins broken. Could the hammer behind the bolt have been possibly too forceful? You speak of homemade pin, I wonder if someone fitted a homemade spring that was too powerful?