M1A gas/cycling issues... match tomorrow :(

[elenius]

My previously super reliable M1A had started to act up.

I went to the range to function test it before my match tomorrow. 3gun in Sac, 2h drive, so I really want my stuff to work. I've never had a problem with it before, but I had changed to Sadlak op guide spring guide and their gas piston. And lo and behold, the gun wouldn't cycle properly. I could see the op rod moving a bit when shooting, but not enough to eject or feed.

So, I figured it must be the new gas piston being too tight, so I took it out and thoroughly cleaned the piston and the gas cylinder, and put it back in. It slid much easier back and forth, so back to the range to try it again. Now it would cycle enough to eject but not feed the new round I took it out and put the original piston in. Same result.

At this point, I talked to a guy at the range, and he lent me a few factory rounds to try. I tried a couple in either magazine I had with me, and one of them cycled it properly, the other not! At this point, I realized that I had run all the previous rounds through the same mag (or at least I think so), so one possibility is that that mag is bad, and hopefully my other mags work. But the mag seems ok and looks and behaves just like the other mags as far as I can tell... And even if it was a bad mag, I don't think it explains the behavior of my first range test, where it wouldn't even eject.

I also changed back to my original op rod guide, so that everything is back to the way it was back in the good old days when it was working, but I don't have time to go back to the range a third time.

Couple of questions:

Could the sadlak NM spring guide actually have caused the problem?

How easy is the gas piston supposed to slide back and forth when I lean the rifle over with the op rod locked back?

It does slide by itself as it is now, but it hesitates a little bit. Also, after I did my second range test, it moved very slow, after only 20 or so rounds after the first thorough cleaning. My ammo (reloads) seems very clean. There is very little gunk inside the gas piston. The first 500 rounds I fired through the gun were filthy Russian Silver Bear ammo, but like I said, I believe I have cleaned everything as much as is humanly possible. It used a pistol cleaning rod and ran patches with Hoppe's No9 through it, followed by clean patches, followed by patches with alcohol (to get the hoppes out and make it dry), and clean patches again.


HELP!!!

[adamsreeftank]

It may be too late, but anyways...

The gas piston should slide slowy when you lock the bolt and tilt the rifle.

If the spring guide is oversized or your spring is out of spec, it could be binding.

[dixieD]

You should check that the locking ring is tight. Once when I reassembled after cleaning the gas cylinder locking ring was one turn out and my rifle would not cycle as you describe.

[c good]

Spring guide could be binding as mentioned before. Have you greased the bolt roller lately? Piston should rock back and forth freely when bolt locked back. Also be sure to check your gas cut off valve is in on position, screwdriver slot should be in vertical position. You mentioned some dirty ammo, maybe it clogged up the gas ports. This is very rare but should be considered. HTH c good

[Wedge]

I have a M1A Loaded Standard, I switched to Sadlak Operating Spring guide and a National Match Gas piston with the slot in it. Also a Tubbs SS Operating spring. I have had no problems at all with the rifle. But when the rifle was brand new it had some cycling issues, FTF,FTE so I switched to a USGI Extractor,ejector and the springs also and those problems went away. Then I added the Sadlak parts. My rifle functions flawlessly. Sadlak parts are top notch. my bet, the ejector,extractor are the problem. Springfield armory Inc. Ejector,extractor's are the weak link in a nice Battle Rifle. I get my parts from Fulton Armory the have a great web-site, plus they have a good customer service Dept. Wedge

[30Cal]

Without a doubt, it's the grooved NM piston. Take it and toss it in the trash. First off, it's not going to work unless your shooting heavy match bullets (168s, 173 and 175s). They generally won't cycle with ball ammo.

The big service teams used the grooved piston for all of about 2 weeks before they went back to plain USGI pistons.

[elenius]

Oh wow, lots of great replies! I decided not to go to the match, but I still want my rifle to work.

Let's see...

The gas piston should slide slowy when you lock the bolt and tilt the rifle.

Yes, that's what it does now. Another observation I made: Without the gas plug screwed in, it slides back and forth very easily. With the gas plug screwed in, it's just a little bit slower. I assume this is because it takes a little while for air to get sucked in through the gas port to fill the vacuum behind the piston as it moves?

You should check that the locking ring is tight. Once when I reassembled after cleaning the gas cylinder locking ring was one turn out and my rifle would not cycle as you describe.

Pardon my ignorance, as you all can tell I'm pretty new at the M1A, but what's the locking ring?

Spring guide could be binding as mentioned before. Have you greased the bolt roller lately? Piston should rock back and forth freely when bolt locked back. Also be sure to check your gas cut off valve is in on position, screwdriver slot should be in vertical position. You mentioned some dirty ammo, maybe it clogged up the gas ports. This is very rare but should be considered. HTH c good

Ah, the bolt roller. I could use some help on this, because I'm not 100% sure how it's supposed to work. Is the silver part supposed to rotate during the whole travel of the bolt? What is its purpose? Mine just slides without rolling, except for the first part, where it comes up from the recess in the op rod, where it does indeed roll a little bit. I've tried to press in some grease into it before, but I only just now did it properly. I followed a suggestion I read somewhere of cutting of a 40S&W case and using that to press in the grease. Worked great.

The gas cut off valve is in the correct position. (And if it wasn't, it wouldn't cycle at all, would it?).

How do you clean the gas port? (Why did you use plural? I'm thinking of the port between the barrel and the gas cylinder. Are you also referring to the port on the bottom of the gas cylinder?)

Wedge -- My problem is not so much FTE or FTF, as it is Failure to Cycle. However, I'll keep your suggestion in mind for if/when I do get those sorts of problems.

30cal -- It's not the piston, as I had the same problem when I changed back to the original one. But I'll look out for problems with the Sadlak one (yes, it is the NM one with the groove, TiN coated).


All, I just noticed something else. There is sort of a ridge on the "ledge" on the right part of the receiver, where the bolt slides over it. See picture. When I hand cycle it, I also notice more resistance starting at this point. Could this be a lousy forging job by Springfield? Seems like a bad place to have a seam in the mold, but that's kind of what it looks like.

[elenius]

Aha!

Looks like dixieD was right. I looked it up in "The M14 owner's guide" by Scott Duff and John Miller. Sometimes it pays off to RTFM

The gas cylinder lock was actually TWO turns out! I assume the problem was that this makes the gas port in the barrel misaligned with the gas port in the gas cylinder, leading to not enough gas pressure to cycle properly.

I'll report back after another range trip.

I'm still worried about that weird ridge/edge/burr on the receiver

[30Cal]

Aha!
...

I'm still worried about that weird ridge/edge/burr on the receiver

It's on the USGI drawing, and you can see it on every M1 Garand as well. I dunno what it does, but it's supposed to be there.

I'd scrap the piston. Sadlak makes great stuff, but I can't figure out why that grooved piston continues to exist. Mike himself says:

It should be pointed out that the grooved piston is intended for use with high powered ammo, not lower grain or ball surplus. With lower powered ammo, the groove has the potential to bleed off too much of the gas which could result in improper functioning of the gas system.

[30Cal]

Aha!
...

I'm still worried about that weird ridge/edge/burr on the receiver

It's on the USGI drawing, and you can see it on every M1 Garand as well. I dunno what it does, but it's supposed to be there.


Put the USGI piston back in and leave it. The grooved one isn't known for running well with ball ammo.

IMPORTANT: THE NATIONAL MATCH GROOVE IS INTENDED FOR NM GRADE AMMO ONLY AND IS NOT RECOMMENDED FOR SURPLUS BALL AMMO OR OTHER LOWER POWER AMMO.

http://www.m-14forum.com/upload/showthread.php?t=42070

[elenius]

It's on the USGI drawing, and you can see it on every M1 Garand as well. I dunno what it does, but it's supposed to be there.


Put the USGI piston back in and leave it. The grooved one isn't known for running well with ball ammo.


http://www.m-14forum.com/upload/showthread.php?t=42070

Ok, great, thanks for all the info!
I use 150gr Hornady FMJ BT bulk bullets BTW.

[Astig Boy]

Could the sadlak NM spring guide actually have caused the problem?

The Sadlak NM spring rod guide is your problem. If you havent noticed, the back of the spring guide rod is the latch that the magazine hooks on to. The back tip of the Sadlak NM spring guide rod may be sitting low, which lowers the magazine seating, which can keep the bolt from catching and loading the next round. Change your "Spring Rod Guide" back to your original and I bet you will have no problems. You may want to try different USGI Mags along with your NM guide rod also. Just remember, Springfield Armory Inc M1As are usually not to USGI Spec...alot of aftermarket parts are made to precise USGI spec. May not be the part thats out of wack, it may be the rifle. Best of luck to you.

[elenius]

The Sadlak NM spring rod guide is your problem. If you havent noticed, the back of the spring guide rod is the latch that the magazine hooks on to. The back tip of the Sadlak NM spring guide rod may be sitting low, which lowers the magazine seating, which can keep the bolt from catching and loading the next round. Change your "Spring Rod Guide" back to your original and I bet you will have no problems. You may want to try different USGI Mags along with your NM guide rod also. Just remember, Springfield Armory Inc M1As are usually not to USGI Spec...alot of aftermarket parts are made to precise USGI spec. May not be the part thats out of wack, it may be the rifle. Best of luck to you.

Astig, you must not have read my post about the gas cylinder lock not being tightened

I took it to the range today, worked perfectly with the Sadlak spring guide rod, original (i.e. Springfield) gas piston, and all my mags

[30Cal]

The Sadlak NM spring rod guide is your problem. If you havent noticed, the back of the spring guide rod is the latch that the magazine hooks on to. The back tip of the Sadlak NM spring guide rod may be sitting low, which lowers the magazine seating, which can keep the bolt from catching and loading the next round. Change your "Spring Rod Guide" back to your original and I bet you will have no problems. You may want to try different USGI Mags along with your NM guide rod also. Just remember, Springfield Armory Inc M1As are usually not to USGI Spec...alot of aftermarket parts are made to precise USGI spec. May not be the part thats out of wack, it may be the rifle. Best of luck to you.

I'm pretty sure SA Inc is using GI spring guides. If they had to tune the spring guide to get it to fit right, it'd be pretty evident (it's a stamped part, so any grinding would stand out like a sore thumb).

[Astig Boy]

Astig, you must not have read my post about the gas cylinder lock not being tightened

I took it to the range today, worked perfectly with the Sadlak spring guide rod, original (i.e. Springfield) gas piston, and all my mags

Ok nevermind. LOL

I'm pretty sure SA Inc is using GI spring guides. If they had to tune the spring guide to get it to fit right, it'd be pretty evident (it's a stamped part, so any grinding would stand out like a sore thumb).

I never questioned the SA Inc GI spring guide. But anyways, there are a lot of aftermarket guide rods that are out of wack since most have the mag catch welded on to the rod. Some are so off that you can not latch any magazines on to them. I just know that some SAI receivers are also out of wack(ie a scope mount made to spec wont fit on SAI receivers.)