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Discussion Starter · #1 ·
I just bought a M1A Socom II used. When I took it to the range it failed to eject rounds and reload the next. I can work the bolt manually to eject and feed the next round. I tried three different kinds of ammo and still have the same problem.
I had my brother-in-law fire the gun and I held my finger behind the charging handle and it didn't even move when fired. I took the gun home and severly cleaned it. When I went to clean the gas piston, I had to remove it with a hammer. The piston (after cleaning) doesn't move back and forth in a tilt test. I assume my problem is with the gas system. However, I am new to the M1A platform and am confused by everything I read on the gas piston and gas chamber area. I saw replacement pistons on the net and thought about replacing the piston. I fired the gun after cleaning and have the same problem.
Does anyone have any reccomendations for a fix or for a specialized gunsmith in the Pennsylvania area?
 

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Hi,

Just to clarify, when you re-assembled after cleaning, did you orient the "D" shaft so that it will fall out the bottom of the cylinder, and did you put it back together "dry"? If this checks out, pull the piston and inspect for burrs. etc.

Redraider
 

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Discussion Starter · #3 ·
Redraider,
Thank you so much for your response. I did align the flat part "D" of the piston with the piston chamber and I put it back together dry. But the piston acts like it is seized up in the gas chamber. It does not freely move. The piston has the appearance to be in good shape. There is no pitting. I will check for burs. I thought maybe my piston is warped and should be replaced? I am assuming that the piston should just freely move in the gas chamber and it doesn't move at all. I have to pound it in and pound it out.
 

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MGySgt USMC (ret)
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I have seen a couple of times where people had smacked the rear of the gas cylider with a steel hammer to get it loose and so it would come forward to take it off the barrel. What they did was peen the "D" shaped hole inward so the piston stem could not go in and out smoothly. If that's the case, with needle files and a little care, you can get rid of the peened over metal and the gas cylinder may be OK afterwards.
 

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Discussion Starter · #5 ·
Gus,
I took your adice and lightly filed around the opening of the piston chamber. I also chucked the piston in a drill and polished the piston with 220 sand paper. The piston finally moves freely without having to be beaten in or out. I will take this new change to the range on Friday and see if this has resolved the problem. Thanks for your input!!!
 

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MGySgt USMC (ret)
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Gus,
I took your adice and lightly filed around the opening of the piston chamber. I also chucked the piston in a drill and polished the piston with 220 sand paper. The piston finally moves freely without having to be beaten in or out. I will take this new change to the range on Friday and see if this has resolved the problem. Thanks for your input!!!
Eh, the emboldened part may cause you problems later on, if you took too much off the piston head. Back in the ancient days when we unitized the front band to the gas cylinder with silver solder, we would occasionally cause the gas cylinder to warp a little bit in the area that was soldered. We used to polish that section of the GC out with 600 Grit Crocus cloth so the piston would move freely. However, I am convinced that having to do such polishing or really from the distortion of over heating the GC during silver soldering, caused the rifles to shoot less accurately.

I am sorry I did not think to mention this earlier.

Also, some of the commercially made pistons were garbage and would hang up even in a proper G.I. gas cylinder. Yours might be one of these. I would have suggested you get a G.I. piston before you polished the piston head with 220 grit emery cloth.
 

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MGySgt USMC (ret)
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This would not have anything to do with the gas cylinder sticking, but did you check that the gas cutoff valve was open?
You know, I was thinking about this thread and thought since the OP is a newbie, he may not know to move the spindle valve to being perpendicular to the barrel.

Also, he may not know there is sort of a partial vacuum in the gas cylinder and the piston doesn't usually slide real fast. The piston moves slowly because of that partial vacuum in many rifles.
 

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Discussion Starter · #9 ·
I actually was told about the spindle valve on another thread. The spindle valve was perpendicular to the barrel and the gun failed to eject anyway. Since my last post, I went to the range. After the sanding and filing....the gun now works! For some reason the piston was seized up in the gas chamber. Since I made the changes, the gun now ejects! I am thinking my next plan is to replace the piston. I can't thank you all enough for your input and advice!
 

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MGySgt USMC (ret)
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I actually was told about the spindle valve on another thread. The spindle valve was perpendicular to the barrel and the gun failed to eject anyway. Since my last post, I went to the range. After the sanding and filing....the gun now works! For some reason the piston was seized up in the gas chamber. Since I made the changes, the gun now ejects! I am thinking my next plan is to replace the piston. I can't thank you all enough for your input and advice!
Sounds like a plan!

Also, you are living in the county where one of my MOST "Favoritist" styles of Flintlock Rifle Guns were made and some of the earliest rifles made in this country. Good to see the rifle tradition is alive and well there still.
 
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