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Universal carbine Fix?

Gazz

Stainless
Joined
Sep 7, 2004
Location
NH
I have this Universal M1 carbine type pistol - the Enforcer, that refuses to eject properly. When fired, the empty case gets extracted but not ejected and get trapped between the bolt face and cut out in the receiver. Not a stove pipe, the case is still parallel to the bore. At first I figured it was under gassed so I dismantled the gas block piston assembly and drilled through it to get to the gas port in the barrel. Then I drilled the gas port out with next size up #drill, tapped the hole in the gas block 1/4-28 and added a ball bearing under the 1/4-28 set screw to prevent the gas from leaking but allowing the piston to move freely. I also put a larger diagonal cut into the gas block plug (this is not the same as US issue M1 carbine gas system). I have brushed the chamber out well, removed the bolt and polished the ejector pin bore and made sure the ejector had plenty of travel. All parts seem to move smoothly but it still will not eject the brass! Any ideas?
 
What happen if you cycle the unfired rounds manually? Does the ejector work?
Do you have any sort of recoil buffer to stop the rear motion of the bolt? If so, I would first investiga if, by any chance, the buffer is too thick.

Paolo
 
I have this Universal M1 carbine type pistol - the Enforcer, that refuses to eject properly. When fired, the empty case gets extracted but not ejected and get trapped between the bolt face and cut out in the receiver. Not a stove pipe, the case is still parallel to the bore. At first I figured it was under gassed so I dismantled the gas block piston assembly and drilled through it to get to the gas port in the barrel. Then I drilled the gas port out with next size up #drill, tapped the hole in the gas block 1/4-28 and added a ball bearing under the 1/4-28 set screw to prevent the gas from leaking but allowing the piston to move freely. I also put a larger diagonal cut into the gas block plug (this is not the same as US issue M1 carbine gas system). I have brushed the chamber out well, removed the bolt and polished the ejector pin bore and made sure the ejector had plenty of travel. All parts seem to move smoothly but it still will not eject the brass! Any ideas?

Ammunition has a propellant. How much, how ignited, and with what burn-rate? Barrel length on EACH side of a gas port can matter. Not to mention short stroke and long, the mass of the moving parts, WHERE the peak energy is contributed in time, to what transferred, and where consumed.

If all that was "don't care", we'd have had reliable gas-operation 200 years earlier.

Might there be any OTHER modifications to this truant puppy?

What you just did might be a positive step. Or not.

Does seem to have been jumped onto without much detective work beforehand, though.

Why was that a good idea? And what d'you have to do NOW to figure out which?
 
Thanks for the replies.
The gun shows no obvious signs of having been worked on before and overall is well worn which makes me think it did work well at one time. I understand that there is a careful balance with this kind of system but had recently fixed a GI carbine that was doing the same thing by cleaning out caked up fouling in its gas system. Also fixed an AR in .458 SOCOM that would not eject by opening up its gas port so my best guess at the failure was something to do with the gas system. The universal carbine has a gas block that is welded to the barrel which conceals the actual gas port. At first I wanted to just clean the port as I had no way of knowing if it was plugged with powder fouling or maybe even lead from shooting cast bullets. Drilling into the gas bock was the only way to get to it. Finding no significant fouling, opening the gas port a few thou seemed to be a good guess. If I ended up over gassing it, it could be reduced by a longer gas block plug which was also used to control gas flow in the original design.
I am ashamed to say I have not tried cycling unfired rounds through it. It was not designed to have a buffer and does not have one.
 
Have you looked into dirt/debris in the bolt end of it? As I recall from when I briefly owned one, the Universal bolts are troublesome compared to USGI style carbines as well.

I seem to recall as well, that the slide where the gas piston hits it is pretty soft metal. Mine distorted to the point that lump formed that interfered with the slide's ability to move the full distance without interference. Manually cycling should reveal that.
 
I have disassembled the bolt, polished firing pin and ejector bores and ultrasonically cleaned and lubricated. Everything moves freely. No obvious deformation of the slide either. Unfortunately, I left it at the shop which is closed for a couple of days so I will not be able to get to it until Thursday.
 








 
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