Ak gas piston rivet problem

**Datkid** · January 28th, 2012, 01:07 PM

The other day I went to the range to shoot my wasr ak47. I had stopped at a gun shop for ammo since Walmart never has mine. The guy sold me 50 reloaded rounds. Said they'd have a bit more zip to them.

While shooting I noticed a weird ringing noise in the boom when the gun went off. (rounds were also hollow point) after about 15-20 rouds the bolt got stuck open. There was no round/shell or anything jammed. I took the clip out and cleared the rifle. Still couldn't get the bolt to close.

I ten removed the dust cover an the long spring. Then I saw the gas piston rivet hanging half way out which was preventing the gas piston from entering the gas chamber. I took it home and smacked it back in with a hammer.

Would you say it's broke? Does that happen? Do you think the guy sold me bum/too strong rounds?

**Asmodeus6** · January 28th, 2012, 03:00 PM

I think it was just a bad rivet job. They are supposed to be welded over and ground flush. If yours isn't - that's the cure. You could* also get a pin that fits more snugly and peen the end unrecognizeable after seating it. That should also keep it together for a long time.

*not the correct way though.

**PA Rifleman** · January 28th, 2012, 05:23 PM

Originally Posted by Datkid

The other day I went to the range to shoot my wasr ak47. I had stopped at a gun shop for ammo since Walmart never has mine. The guy sold me 50 reloaded rounds. Said they'd have a bit more zip to them.

While shooting I noticed a weird ringing noise in the boom when the gun went off. (rounds were also hollow point) after about 15-20 rouds the bolt got stuck open. There was no round/shell or anything jammed. I took the clip magazine out and cleared the rifle. Still couldn't get the bolt to close.

I ten then removed the dust cover an the long spring. Then I saw the gas piston rivet hanging half way out which was preventing the gas piston from entering the gas chamber. I took it home and smacked it back in with a hammer.

Would you say it's broke? Does that happen? Do you think the guy sold me bum/too strong rounds?

There are two issues here.

The piston rivet drift was likely the result of the build quality, not the ammunition. This is a very minor issue. As I recall, the primary function of the piston rivet is to prevent the piston from un-screwing itself from the bolt carrier. The rivet isn't a load carrying element. If it keeps drifting out, try pulling it out and adding a small chamfer in the rivet hole. Replace the rivet and peen it over. The chamfer will allow the rivet to peen over and grip the carrier.

While I normally eschew reloaded ammunition with unknown provenance†, AKs are tougher that most people give them credit. I've witnessed .308/147 grain bullets fired out of AKs, the casing was filled to the top with powder and then compressed, more powder was poured in and the 308 bullet compressed everything a little further. The AK kicked a little more, but was unharmed. Since it was a tracer, there was no question the bullet left the rifle, and where it went. [8^)

I do have a question -- was the reloaded ammunition boxer primed or berdan? If berdan, where did you find it? If you aren't sure, see image below:

† Reloads are sort of like sex -- fun, but you need to be really careful with whom you hook up, and for similar reasons.

**Fragger** · January 29th, 2012, 08:36 AM

As others have mentioned not that terrible of a deal but it shouldn't have happened if the pin was installed correctly.

The thread tolerance between the piston and the carrier is very large.
Meaning the piston has a lot of slop (wiggle) when it is being screwed into the carrier.

On the few that I've built after the pin was peined there was a small amount of wiggle/slop in the piston itself. Many believe this to be normal as the reason is to prevent premature wear on the gas tube.
On those builds I've made my own pistons and incorporated the loose fit of the threads. Seated them into the carrier to proper depth. Drilled and pinned.

While the thru hole size and the cross pin should be a close fit the diameter is not critical. As mentioned the only purpose it serves is to keep the piston from rotating either in or out.

So worse case for you would be to have a pin that is too short with no meat on it to pein over. In that case going to a longer pin which needs to be made of soft non heat treated steel would be the fix.
As mentioned chamfer the carrier thru hole slightly to allow for the head of the pin to be formed when peined over. Remove the excess with a file.

**Datkid** · January 30th, 2012, 01:38 AM

I smacked the pin back in with a hammer, I haven't shot it since to know if it's gonna stay. I'm looking at te ticket the reloaded rounds came with.

It reads:

Date: 2003
Cartridge: 7.62x39mm
Case: mix
Primer: LR
WT.: 25
Bullet: 110
O.A.L.: Sierra

I guess if it pops out again I'll try a thread lock?

**nfafan** · January 30th, 2012, 01:42 PM

Was that a TAPCO-marked piston rod by chance?

Reason I ask is that if true; it would confirm that it was the "922 compliance work" that Century jobbed-out to the lowest bidders they use.

Most of my WASRs have been Euro-pistons but lately I have seen several that have had TAPCO pistons.

Only Century knows for sure how many Bulgies, HK93s, Tantals, Yugos, Galils, G3s, Cetmes, Polskis - have been effed-over by their selections of 'smithing outfits.

**Datkid** · January 30th, 2012, 03:23 PM

I don't see tapco written anywhere on it, any other way of knowing?

**nfafan** · January 30th, 2012, 03:42 PM

Originally Posted by Datkid

I don't see tapco written anywhere on it, any other way of knowing?

None that I know of, on the only WASR I have left with a TAPCO piston rod the TAPCO branding is "machined" into the side of the rod - can not miss it.

**Fragger** · January 30th, 2012, 07:58 PM

Originally Posted by Datkid

I guess if it pops out again I'll try a thread lock?

Do you think thread lock will still allow the piston to have a bit of play in the carrier?

**knight0334** · January 30th, 2012, 08:13 PM

Hell, I've played hell a few times trying to get that damn pin out to replace the piston with a US922(r) compliant part. lol I just think yours was just a badly installed pin.