[Rob501]

I'm sure there is a M12 (1940) expert out there that can maybe tell me what is wrong.

In a Trap shot last week the gun fired as I closed the breach. "Yes, almost shot trap house" and "no" finger was not on trigger.
The first time it happened I wasn't exactly sure what had happened. So, I reloaded and continued to shot. About 5 shots later it did it again. After shooting into ground I unloaded and left the line. (the gun was unsafe to shot).
I took the gun home and took apart to see if I noticed anything broke and cleaned everything including trigger. Only thing I noticed was the trigger screw (that holds trigger to receiver) was loose.
I took the gun to the club today to test it. After the 5th shot it did it again. (I know someone will think my finger was on trigger but I closed breath with hand back on stock).
Has anyone had this happen and know whats wrong ? Older gunsmiths that know M12s are hard to find. Rob

 

[racer]

Yes- had it happen at a shoot. Mine had a one broken timing spring. I have a 57 and there are two straight springs about an inch long on left side of trigger(opposite action opening) Older gun may only have one spring.

 

[jeff348]

One of the music wire springs on the action release is broken.

 

[50ralph50]

Did you clean the bolt and firing pin channel. It may have debris in it that holds the firing pin forward to far and when yo uclose the gun it fires it.

 

[Rob501]

Thank you all. 50ralph50 got me thinking about firing pin. I had already checked the springs. Thank you for help. Rob

 

[JohnTrigger]

I believe Jack First sells a reproduction firing pin. Several on eBay too.

 

[Rob501]

I got one on way from MGW.

 

[rpnp2322]

I got one on way from MGW.

I would certainly check the trigger timing when you get things back together! Before you run any live rounds through it. They can get out of time!

 

[Sky Buster]

Send it to Phillips GunSmithing in Texas or Laibs in Minnesota.

 

[rpnp2322]

Send it to Phillips GunSmithing in Texas or Laibs in Minnesota.

It is very easy to see if it is in time! With no live rounds in the gun! Pump it and slowly chuck it forward, with your finger on the trigger. If it is in time the firing pin will not release until the breach is closed!!! If it releases before, you still have a problem. And then you can send it to a competent gunsmith who understands model 12s. Good luck 👍🏼

 

[Rob501]

Thank you all for the advise. I will certainly check that.