I have an old Westernfield pump shotgun that has random misfires. I checked the primers and ever so often it has light primer strikes. It has a free floating firing pin (no spring) that appears to be in good shape. The area where the hammer strikes the firing pin looked rough so I lightly smoothed it with a fine diamond stone and this seemed to help a little. Could it be a weak hammer spring? Any help would be appreciated.
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Shotgun has random misfires
- Thread starter AL45
- Start date
If the spring is weak, I'd expect it to have consistently light primer indents.
My guess is that something is hanging up. Either the firing pin is catching or dragging on something, once in awhile or the hammer is sometimes hanging up or dragging on something and not delivering a full strength strike all the time.
If the hammer rides in a channel, I'd look at the edges of the channel and the edges of the hammer to see if there's evidence of the hammer dragging or hitting. Also check to see if the fit of the hammer on the hammer pivot pin is tight or if it's loosened up allowing a lot of side to side play or tilt in the hammer. That could let it hang up or catch on a part that it normally would miss if it didn't have that play.
Check the firing pin and firing pin channel to make sure there are no burrs that could be slowing the firing pin down.
My guess is that something is hanging up. Either the firing pin is catching or dragging on something, once in awhile or the hammer is sometimes hanging up or dragging on something and not delivering a full strength strike all the time.
If the hammer rides in a channel, I'd look at the edges of the channel and the edges of the hammer to see if there's evidence of the hammer dragging or hitting. Also check to see if the fit of the hammer on the hammer pivot pin is tight or if it's loosened up allowing a lot of side to side play or tilt in the hammer. That could let it hang up or catch on a part that it normally would miss if it didn't have that play.
Check the firing pin and firing pin channel to make sure there are no burrs that could be slowing the firing pin down.
Blindstitch
New member
I did a search and found this.
The Western Field Model 40N was a 12ga made by Noble for Montgomery Wards between 1953 and 1971.
The Western Field Model 40N was a 12ga made by Noble for Montgomery Wards between 1953 and 1971.
Dixie Gunsmithing
Moderator Emeritus
Since it is intermittent, it could be a few things.
It could be bad ammo. Did you try any other brand, etc, and receive the same results? If not, then:
First, the bolt and firing pin could be dirty, and that keeps the firing pin from striking the primer hard enough. Also, the hammer could be dirty.
Second, the hammer spring is getting weak.
Third, the firing pins nose might be getting worn down, and some primers might not fire if they are recessed a little lower than others. The nose on the pin should be a domed or half-hemisphere shape, with no flatness.
It could be bad ammo. Did you try any other brand, etc, and receive the same results? If not, then:
First, the bolt and firing pin could be dirty, and that keeps the firing pin from striking the primer hard enough. Also, the hammer could be dirty.
Second, the hammer spring is getting weak.
Third, the firing pins nose might be getting worn down, and some primers might not fire if they are recessed a little lower than others. The nose on the pin should be a domed or half-hemisphere shape, with no flatness.
Dixie Gunsmithing
Moderator Emeritus
One thing you might try, before ordering a spring, is trying to give the old hammer spring a slight stretch. That could help show whether it is the problem or not. If it does fire okay afterwards, then order a new spring.
If it was to be headspace, as mentioned above, then it will be hard to repair. The bolts top rear could be worn and cause it, or the recess in the receiver that it sets into. The only fix would be either trying a new bolt, or setting the barrel back by its threads, and the latter would cost way more than it's worth.
I think this is a Noble model 40, and a breech bolt runs $40.00. Hopefully, it's not this.
The hammer spring, 17520A, is $3.10 from Numrich.
If it was to be headspace, as mentioned above, then it will be hard to repair. The bolts top rear could be worn and cause it, or the recess in the receiver that it sets into. The only fix would be either trying a new bolt, or setting the barrel back by its threads, and the latter would cost way more than it's worth.
I think this is a Noble model 40, and a breech bolt runs $40.00. Hopefully, it's not this.
The hammer spring, 17520A, is $3.10 from Numrich.
Blindstitch
New member
Got any pictures or info to tell if this is a pump or bolt shotgun.