HELP! Burrs in my Norc M14 gas cylinder!

philchau

philchau

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I went out to run my M14 this weekend. Noticed that it wasn't cycling the rounds at all. Took it home to take apart the gas system and I noticed that the piston was jammed into the cylinder. Took a mallet to knock it loose.

Took a look onto the inside of the cylinder and this almost a little ridge of raised metal on the inside lip of the cylinder. The piston will not slide through the cylinder anymore. How do I fix this? Do I need a new cylinder? HELP!
 
Sounds like the piston was too small for the cylinder.
Got pic's?
Any way it sounds like it's pouched and you should be on the hunt for a new 1.
 
Really need more info for a cause: is it new, old, a welded utinized gas assembly, heavy loads, did the piston rattle before, etc.... ? ? ?

A new one sounds right, but a cause would be good in case: 1)It may happen again and 2)Maybe help others prevent it!!
 
I've seen this happen when folks use a screw driver to tighten up their gas lock....the result is a small pinch-like dent on the inside if the cylinder that impedes free piston movement. If thesis the case I would recommend replacing it. Send me a pm...We can hammer out a deal on either a Chinese takeoff or American made.

Cheers,

Brobee
 
I just got a new complete cylinder and piston from 7.62 just this past week. It took exactly 1 week from order to my door, but they're not cheap
 
Hi guys,

here are some pics of the cylinder.

XNca2l.jpg


eTs0Hl.jpg


I KNOW that little lip shouldn't be there.

Can I take a dremel or a file to file it down? Or do I really need a new cylinder?
 
just a heads up to all...... I have seen this same bur on several rifles sent in for work.
I've caused this burr myself back in the early days.
How did i manage that you ask?
by tightening down the gas plug on the cylinder prior to ensuring the piston was indeed protruding from the cylinder at the burr end, crushing the piston tip against the inside of the hole where the burr is.
ALWAYS check for piston protrusion prior to tightning the gas plug ;)

This is not an ideal fix and a new gas cylinder is recommended, BUT try very gently with an extremely fine file to return that edge to flat. Then check piston movement past the repair.... then finally check for piston vacuum once it's all back together.
 
Absolutely !

M14Doctor said:
just a heads up to all...... I have seen this same bur on several rifles sent in for work.
I've caused this burr myself back in the early days.
How did i manage that you ask?
by tightening down the gas plug on the cylinder prior to ensuring the piston was indeed protruding from the cylinder at the burr end, crushing the piston tip against the inside of the hole where the burr is.
ALWAYS check for piston protrusion prior to tightning the gas plug ;)

This is not an ideal fix and a new gas cylinder is recommended, BUT try very gently with an extrememly fine file to return that edge to flat. The check piston movement past the repair.... then finally check for piston vacuum once it's all back together.
Click to expand...

Like he said !

I have had a few (not many) like that brought to me over the last few years and a file cured all .:)

:ar15:
swingerlh.gif
 
M14Doctor said:
This is not an ideal fix and a new gas cylinder is recommended, BUT try very gently with an extremely fine file to return that edge to flat. Then check piston movement past the repair.... then finally check for piston vacuum once it's all back together.
Click to expand...

Thank you M14Doc! This worked and the piston is back in working order.

How do I best check the piston vacuum?

Lesson learned, don't tighten the gas cylinder until the piston is keyed in place.
 
Thanks go out to all of you for helping out in this situation. I love it when all of you save me a pile of typing! Life is good here in this M14 Forum. :cheers:

:D Barney
 
philchau said:
Thank you M14Doc! This worked and the piston is back in working order.

How do I best check the piston vacuum?

Lesson learned, don't tighten the gas cylinder until the piston is keyed in place.
Click to expand...

once the gas system parts are installed and tightened up, point the muzzle up and using your finger, push the piston into the cylinder and quickly let go.
if it drops like a stone...... that's bad and there is insufficient vacuum.... means new cylinder or new piston
if it drops and appears to have resistance... as in it drops slower than a stone hehehe .... life is good and you have piston vacuum.
 
I've seen that burr on brand new cylinders before. One of the three 762mmfirearms cylinders I ordered came that war. They told me it happens sometimes when they broach the D-cut in the face and the one I was sent slipped past QC. They offered to replace it for free, but I fixed in about 5 minutes.

The fix is simple enough. CAREFULLY use a small needle file to remove the burr - it should work just fine after that.

Cheers.
 
yes, exactly; a touch of mindful filework would straighten that out.

As in; don't just start filing the poop out of it! So many goog things pooches due to over zealous filework... :(
 
I'm a total M14 noob and want to thank you guys for possibly saving me the same mistake.:wave: I like to be a leader but in these cases it's better to learn from others.:rolleyes:
 
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