M1A failing to extract

angryeyebrows

angryeyebrows

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OK so I'll admit I'm new to the platform. I bought a used M1A, disassembled it and re-assembled it into a Sage EBR Chassis. The rifle is not functioning correctly. I've built many AR's and am no stranger to mechanics, but I just don't know this system fully yet.

The rifle fires (sometimes two or three rounds) and then fails to extract the empty casing.

To me this screams gas problem but I'm gonna throw it out there for the M14 gurus to help out.

The gas system seems nice and tight. The Sage requires the replacing of the handguard front band with a crush washer. When I tightened the gas lock it snugged right up.

Any ideas of what to check?
 
Check the extractor to make sure it's not worn, chipped, etc. Also, do the gas piston check - open the action with the upper out of the stock and tilt the rifle up 90 degrees - does the piston have air vacuum and take 2-3 seconds to fall, or does it drop instantly?
 
Grease the :

Bolt lugs (x 2)
Op rod track
bolt raceways
hammer face on trigger assy

Tighten gas plug (hand tight is fine)
Ensure spindle valve (just in front of the front band) is straight up and down?
Handloads or factory ammo?

Please get back to us!

Cheers,
Barney
 
tiriaq said:
Chamber clean?
Click to expand...

I don't think it's dirty enough to prevent extraction...if it is after so few rounds, maybe the M14 is not for me.

Claven2 said:
Check the extractor to make sure it's not worn, chipped, etc.
Click to expand...

Extractor looks ok?? The brass does take a bit of a beating though. Normal?

Claven2 said:
Also, do the gas piston check - open the action with the upper out of the stock and tilt the rifle up 90 degrees - does the piston have air vacuum and take 2-3 seconds to fall, or does it drop instantly?
Click to expand...

Piston does not drop at all. I disassembled the rifle completely and investigated the piston/gas cylinder area thoroughly. With the gas cylinder completely off the rifle, the piston moves freely and when I assemble it together with the gas lock and gas cylinder nut (off the rifle) it does have a bit of suction.

Is it possible to tighten the gas lock too tight and cause the piston to bind?
 
Hungry said:
Grease the :

Bolt lugs (x 2) Check!
Op rod track Check!
bolt raceways Check!
hammer face on trigger assy Check!

Tighten gas plug (hand tight is fine) Check!
Ensure spindle valve (just in front of the front band) is straight up and down? Check!
Handloads or factory ammo? Factory Federal
Click to expand...

I watched as much videos as I could find! Including yours!
 
angryeyebrows said:
OK so I'll admit I'm new to the platform. I bought a used M1A, disassembled it and re-assembled it into a Sage EBR Chassis. The rifle is not functioning correctly. I've built many AR's and am no stranger to mechanics, but I just don't know this system fully yet.

The rifle fires (sometimes two or three rounds) and then fails to extract the empty casing.

To me this screams gas problem but I'm gonna throw it out there for the M14 gurus to help out.

The gas system seems nice and tight. The Sage requires the replacing of the handguard front band with a crush washer. When I tightened the gas lock it snugged right up.

Any ideas of what to check?
Click to expand...

I had a similar problem with my M1A. The only thing that seemed to help was a boot on op rod. Clean your chamber vigorously.
 
I've had problems with SA extractors failing after very few rounds. Try switching it out for a GI m14 or garand extractor, might work. Marstar sells garand extractors and will work in your m1a.
 
I've also never had an issue with a Chinese extractor - they are better made than the M1A extractor.

If you use an M1 extractor, make sure it does not protrude below the bolt body. Most of the M1 extractor's I've fitted had to be ground at the base of the stem as the M1 extractors are often a mm or so longer then the M14 extractors.
 
I don't think it's the extractor. I think I misdiagnosed it. The rifle sometimes fails to cycle after the round is fired, leaving the empty casing in the chamber.

I reassembled the gas system after polishing the back side of the gas lock. It takes less force this time to snug it up and the piston moves freely with a bit of suction. Gonna head out an blast a few rounds to see if it's good to go.
 
The piston is supposed to have a bit of suction, that is normal.

angryeyebrows said:
I reassembled the gas system after polishing the back side of the gas lock. It takes less force this time to snug it up and the piston moves freely with a bit of suction. Gonna head out an blast a few rounds to see if it's good to go.
Click to expand...

Why would you do this? Changing the backside of the gas lock may affect the gas timing due to possible change in alignment of the piston hole to the cylinder hole, which itself must be aligned with the barrel hole.
 
Winz said:
The piston is supposed to have a bit of suction, that is normal.
Click to expand...

Yes so I've discovered.

Winz said:
Changing the backside of the gas lock may affect the gas timing due to possible change in alignment of the piston hole to the cylinder hole, which itself must be aligned with the barrel hole.
Click to expand...

I guess if you were to drastically change the dimension. In any case, after the range today, the rifle functions great. Turns out the gas lock was too tight.

How munched does the brass get with the M14 action? The one side of the rim of my casings is a little ragged looking. Normal??
 
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