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Old November 22, 1999, 12:43 PM   #1
Join Date: June 26, 1999
Posts: 67
One of my friends has an Iver Johnson M1 Carbine, sometimes it fires and sometimes it doesnt.

Sometimes you can pull the trigger, and hear the hammer hit, but nothing happens. The firing pin is hitting the primer and denting it.

My theory is that the hammer spring is weak and needs to be replaced, but is there anything else that will do this?


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Old November 22, 1999, 01:23 PM   #2
4V50 Gary
Join Date: November 2, 1998
Location: Colorado
Posts: 19,392
Try out a different brand of ammo. Could be hard primers.

Alternatively, disassemble the bolt and clean the firing pin and its channel of any accumulated grease. Grease can slow down a firing pin such that it doesn't have enough energy to ignite the primer. Check the firing pin for burrs and polish it out if there are any. Also, after you clean the firing pin channel, shine a light down from the bolt face to see if there's any burrs.

Another possiblity could be whether the trigger housing unit has been drilled correctly for the hammer pivot pin. If it's off, the hammer won't transfer as much energy as it should.

Finally, make sure the bolt is fully locked up before squeezing the trigger. If it wasn't, the gun shouldn't fire (out of battery). Op rod (slide) could be bent or out of spec.

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[This message has been edited by 4V50 Gary (edited November 22, 1999).]
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Old November 24, 1999, 01:03 AM   #3
James K
Join Date: March 17, 1999
Posts: 24,189
Hi Grenadier,

Could also be either excess headspace or short cartridges; either will result in the cartridge not being supported and cushioning the firing pin blow.

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Old November 24, 1999, 01:22 PM   #4
Join Date: June 26, 1999
Posts: 67
Thanks guys!

I will detail strip/clean/examine the bolt and trigger assemblies this weekend, and try and brain this out.

Im hoping it isnt a headspace problem. I can (probably ) fix most anything else.....


[This message has been edited by Grenadier2 (edited November 24, 1999).]
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