cycling failure.

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Originally Posted by jbernat315

Tim- the clip does not eject after the last round is fired.
jak- "they" is an individual that I was referred to by a gunsmith who had more knowledge in M1's than he did. He was also the one who suggested getting the adjustable plug and/or military surplus ammo. the part number is 6536382-J.
Musketyjon- I measured the hole by putting a 5/64drill bit into it. it fit snugly into the hole.
cannonshooter- the gas port holes line-up.

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So this is a Commercial barrel or GI barrel? 5/64 hole size is fine, no problem there. We know this much, I think;

1. The piston is correct size
2. Cannonshooter makes a good point. Not only make sure the barrel port is centered in the gas window of the cylinder but also that you unscrew the gas lock as much as you can allowing the cylinder to come off the rifle as much as possible with the hole still in the window. Then install your lock screw.
3. We don't know if your gas cylinder, either one, passes spec
4. We don't know how long your oprod spring is.
5. We don't know if the ammo you're using is even as potent as GI HXP.

Look no further, I am the “they” that looked at jbernat315’s M1. And knowing what I don’t know I referred him here. I happened to be at the gun shop trading a M1 for a new duck gun, yes it hurt to do it, when jbernat315 brought in his M1.

The piston is .5262 and round, a visual inspection of the oprod did not reveal any obvious ‘bad bends’ but there was contact between the op rod and the stock. Tilt test failed so we identified the contact points and he said he relieved it and it now passes. No gauge to measure either of the gas cylinders. The gas lock screw appeared to be OK. It was lubed and there were no obviously worn parts. After finding out he was shooting commercial ammo I did visually inspect the receiver for any signs of cracking, nothing. My first guess was the op rod contact so I recommended he fix that and get some HXP or an adjustable gas plug before shooting/troubleshooting any more.
Things I did not check include headspace (no gauges available then), chamber finish/cleanliness, barrel spline diameter, spring test, or muzzle wear. I was betting the oprod contact would solve the problem.

I think it would be good to get a new spring in it and some HXP.

Jbernat315 - Hopefully we can link up at the range and I will supply the HXP, spring and if needed swap a few more parts for troubleshooting while there. I can also try to borrow a gas cylinder gauge to check them.

Aren’t the correct drill index numbers 47 and 46 go and nogo? My book is loaned out but these are marked in my index. Or am I total out there on these?

Another point Elvis just made me think of, check the inside of the oprod for a piece of old spring. There is to much spring on this rifle or not enough gas. If it tilts, it has to be one of these two.

Oh, check the back of the stock for bolt strikes on the inside. If so, get that cleaned out. This was per Punch The Clown

Two more things:
1. Back the lock off one turn from wherever it is.
2. Grease the op rod spring generously.

Bob,

What duck gun did you get?

Ok - rlelvis and I got together yesterday and started swapping parts to figure out what was not functioning properly.

1) The gas cylinder had some play in it allowing for gas to escape at the gas port before it reached the gas cylinder.
2) The gas plug venting spring was not functioning properly, likely allowing gas to escape the cylinder.
3) There may be a problem with the operating rod because when that was swapped it worked before changing out the gas cylinder and plug.

I have the gas cylinder and an adjustable gas plug, so it appears to be cycling properly now. Probably going to chang the operating spring and perhaps look into operating rods.

The only other issue noted at this point is that it tends to flatten the primer of the casings.

Regarding number 1. , told you punch the clown! Punch and I discussed that one on the phone. It is a small amount of gas to be lost but it adds up. Here's the thing though, just tightening the cylinder won't help. If this is truly a problem then only a new cylinder or barrel will fix it. There would be a gap there that needs closing.

I don't understand number 3.

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Originally Posted by jbernat315

The only other issue noted at this point is that it tends to flatten the primer of the casings.

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Commercial ammo? Dry chamber I hope.