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Posted: 3/26/2016 1:36:41 AM EDT
| I bought a CMMG MK-3 AR-10 about a year ago from cabelas. I haven't had a chance to shoot it until about a week ago as Iv been gone to college and not been home very often. Anyways when I tried to test it out finally, it just will not fire! So I was wondering if anyone else had this issue with this or any other gun? Also, any ideas what the problem might be? Thank You for any input! |
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Gonna need some more info.
Did you load the magazine and insert it properly? Did you charge the rifle and verify that a round was chambered? Did you disengage the safety, if you had previously engaged it? Presuming the above - what happens when you press the trigger? Nothing, or a sound of the hammer falling but a failure to fire? Did you eject the failed to fire round if applicable and inspect it for an indentation from the firing pin? Did you verify that your bolt has a firing pin installed, and have you checked the protrusion, or at least that it does protrude? |
| Can you push on the firing pin to make it protrude? If not, this is your problem. Does the AR10 have a firing pin spring or is it a true AR15 in that respect? Does the firing pin rattle back and forth if you shake the BCG? If you can't solve it or find someone local who can, you'll have to return the upper assembly to CMMG. They'll need the whole upper in case it needs a new bolt. |
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Check protrusion by removing the BCG. Press the both fully into the carrier, and put one finger on the bolt face, and your thumb or another finger on the back of the firing pin and give it a little nudge. By design the firing pin can only protrude when the bolt is fully telescoped closed into the bolt carrier, then only a little bit, but you'll be able to feel it protruding if you push forward on it in that closed/locked position.
If the firing pin doesn't protrude in that position, there's a spec issue with your bolt or carrier or firing pin. If it does, then your issue lies in the bolt failing to fully chamber, since that's the only way the hammer falling on a loaded round wouldn't leave a firing pin impression at all. |
The CMMG rifle you have uses a firing pin that has an additional shoulder that is forward of the traditional AR15/M16 type firing pin. Make sure that the firing pin retaining pin is put in correctly between the back two heads of the firing pin.
CMMG is an Industry Partner on this forums, you might try getting in direct contact with them if you cannot figure it out. CY6 Greg Sullivan "Sully" SLR15 Rifles TheDefensiveEdge.com (763) 712-0123 |
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