M1 Carbine - Problem Ammunition

[ping]

I ran into a situation today that I need some help on. I got my carbine from CMP about a month ago and it looks great. It is an Inland model. I bought some UMC (Remington) ammo at the gun show and it shot fine. So I figured I would be a bunch more so I bought Aguilar from CMP. Well just got back from the range and about 50% would not fire. In viewing the cartridge you can see where the firing pin put a dimple into the primer but barely. It is discernable though. It is like the firing pin cannot hit the primer fully like it did on the old UMC ammo. My buddy has an Inland also and shot with me today and he was able to fire the same ammo with no problem.

I did notice one thing though his bolt is of the flat type where mine is round. Guess they must have changed these at some point during the war. Any help on this would be great. Maybe the UMC is more like the old USGI and that is why. Is there a disparety of ammo that does not do well in all carbines.

Thanks in advance

 

[dafitch]

Have you taken apart the bolt and cleaned the firing pin channel? I think you'll be surprised at all the cosmoline stuck within the smaller parts.

 

[45B@cav]

If it is clean already, You may have a firing pin protrution problem. I have seen firing pins worn just enough to not make proper contact with primers. If the Ag primers are a little harder than the UMC primers this may be the problem. To fix it install a new firing pin.