wasr 10 sticky piston

Hey fellas, I got a slight problem with my new(to me) wasr. The first time I took it out, just put 40 rds through to make sure it wasn't a lemon. No hiccups. A few weeks later, after neglecting to clean it from the previous time, I shot off close to 200 rounds. When it started to heat up, the action would get really hard to cycle....like unload it and go wild on it trying to get the bolt/piston back. so I could fire it. I was only able to after I let it cool down a bit, and then sometimes the action would not fully close. A 1/4" gap was left between the receiver and the bolt carrier, but it still shot fine. A shot of rem oil in the gas tube helped alleviate the problems, for the most part.

I just want to know if this is normal with some aks. I was kinda under the impression that they are rugged, like going through 200+ rounds and not clogging up to the point of complete non-function. Or is my only option to always run it with a shot of lube over the piston head/in the gas tube? Maybe it is still just getting the kinks worked out?

Otherwise, its a fine little rifle and a ton of fun to shoot :D

are you sure the piston is not bent in anyway? heat will cause metal to expand, but ak tolerances are not tight at all and for it to expand so much as to cause binding, that I never experienced. Also, is it the piston or the receiver rails the bolt rides on heating up and deforming thus making the bolt stick and making it hard to cycle?

You should not lube the gas piston. Clean the gas port thoroughly. An old toothbrush soaked in Hoppes #9 can be shoved in there and rotated around. Twist a rag (or paper towel) up and rotate it around in there to get the Hoppes residue out. Repeat a few times and wipe it dry well. Likewise, clean the piston with brush & solvent and then wipe it dry.

Lube/oil/grease on the gas piston collects the carbon & gas that acts against the piston to cycle the action. You may have accumulated so much filth on the piston head and in the gas port that the piston could not travel all the way forward.

Does the piston wobble or is it fixed in place tight to the bolt carrier?

Have you checked the gas block (angled piece connected to the barrel the piston head comes to rest in?) for straightness with the front trunion / receiver?

Does your gas tube fit properly? Is it hard to remove? Is it sloppy or sit crooked?

When in doubt take CLEAR pictures of the area's that could be the problem and effected parts and someone will probably SEE something if there is genuinely a problem.


Check all parts on the rifle for signs of HEAVY - or abnormal wear. Shavings, bits of shiny metal near the bolt lugs, rails, hammer, etc.

Does the gas piston head have any marks in it, or on it?

Is the rifle soaked down with lube and now coated in fouling?

When you first shot it, the 40 rnds, were you using some of the brass cased corrosive ammo going around?
Corrosive ammo won't hurt a chrome lined bore, but it can be a bugger on a blued steel gas tube if left to set around for weeks at a time.

Either way, like said above, clean out the gas tube, clean the piston. Check for a bent piston. No lube on the piston, a few drops where the bolt rides in the receiver is good.
Make sure that the trigger group is all in good order, strange things can happen to an AK when pieces of the trigger group get out of whack.

Thanks for all the advice, guys. Piston was true, cleaned it well, reassembled...ran 160rds through it again. Happy to report that there were no problems with the bolt carrier sticking, though it did have the quarter inch gap 1 time. I just slapped the handle forward and it popped right in place. :)

ETA: I've only run wolf military classic and golden tiger, no brass. Would you happen to know the name of that corrosive ammo?

It's Yugoslavian brass military surplus. That ammo is corrosive.



Is your gun hard to rack? Does it hang excessively hard when it goes over the hammer, or when it's about to be all the way forward? (when the bolt lugs engage?)

Did you buy the rifle "new"? If so, did you make sure you cleaned all the cosmoline out of it? The WASR's aren't coming in as cosmo-soaked as they used to, but unlike many new-in-the-box guns these are not ready to shoot.

You need to clean all that stuff out of there or it will gunk up inside the gas system and prevent the weapon from cycling properly. Eventually, it will all burn off, but until it does it can cause issues.

You could also be having a problem with your magazine. If yours came with one of the new Tapco mags, they aren't always perfect. Sometimes they need to break in--or in some cases just don't work. This can present as feeding problems, bolt hangup etc.