AK piston question


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SATX man
March 26, 2009, 12:14 AM
when I cleaned my rifle I noticed the poston was loose it woobled alittle is this normal?

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gvnwst
March 26, 2009, 12:18 AM
Depends, what make and model of rifle do you have, and was it going from side to side, or front to back?

chris in va
March 26, 2009, 12:19 AM
FWIW the piston on my Saiga is rock solid against my bolt carrier/handle.

SATX man
March 26, 2009, 12:19 AM
It's an Arsenal 107f it woobles side to side.

Hoppy590
March 26, 2009, 12:50 AM
AK pistons are meant to wobble a little. it should be threaded (screwd in) and pinned. NOT WELDED!

a little wobble is OK. side to side, up and down is fine.

WardenWolf
March 26, 2009, 01:30 AM
If it only wobbles a little, no problem. If it's bad, it can lead to premature wear in the gas tube. It's not a big deal to replace it, although you should have a gunsmith do it. Main thing is to ensure it's screwed down tight before they drill the pin hole in the new piston. A piston is considered a compliance part, so if you do it, go American.

Ian
March 26, 2009, 02:35 AM
Some wobble is just fine; that's how the guns were designed to be. If you look at parts kits (which still have the original military carrier/pistol fit) you'll find that virtually all of them have some wobble. Not having any movement between the bolt carrier and piston can impair reliability.

No need to worry about your 107f.

Sam1911
March 26, 2009, 05:44 AM
As the others have said, a bit of wobble is just fine.

The Kalashnikov system has enough natural clearance to run whether the piston is tight or loose. The only argument I've ever heard that made a whole lot of sense one way or the other is that leaving a little "play" in it allows a bit of flexibility so that if there are any mis-alignments between the axis of the gas tube and the receiver rails, the bolt-carrier & piston assembly can flex a bit to compensate. That could, in theory, reduce wear on the rails, piston head, carrier lugs, bolt lugs, etc. -- but I've never seen an AK that was so precisely fitted that it could ever bind, or that was such a precision instrument that a bit of extra wear would hurt it.

The standard operating procedure on doing an AK build where you'll be replacing the gas piston is to screw the new one in tight, then back it out 1/8-1/4 of a turn, drill it, insert the pin, peen the pin, grind flush, re-finish.

It's not a big deal to replace it, although you should have a gunsmith do it. Uh, why? If you can operate a drill and a hammer, this task isn't exactly challenging.

-Sam

Mr. Bojangles
March 26, 2009, 06:38 AM
Wobble? In an AK? nawww. They aren't supposed to rattle when you shake them either. :scrutiny:

nalioth
March 26, 2009, 02:12 PM
Mr. Kalashnikov designed the pistons with 'wobble'.

zoom6zoom
March 26, 2009, 03:55 PM
...but they don't fall down.

turkeythigh
March 26, 2009, 07:03 PM
like many have said before me in this thred. ak's are designed to be a bit rattley and wobly that is part of what lets them go for ever and ever with out breaking down.

Kymasabe
March 26, 2009, 09:36 PM
I'd worry if mine didn't rattle a little :eek:

Hoppy590
March 26, 2009, 10:33 PM
I'd worry if mine didn't rattle a little

its kinda like how i drive an old BMW, and since i can no longer get asbestos brake pads, my brakes make noise when i brake.

its when the car STOPS making noise, i check the brakes out.

PT1911
March 26, 2009, 10:35 PM
easy fix for it... drop it in the mud... will tighten things right up....

Badger Arms
March 26, 2009, 11:12 PM
AK pistons are meant to wobble a little. it should be threaded (screwd in) and pinned. NOT WELDED! A little wobble is OK. side to side, up and down is fine.

+1 on this.

The Kalashnikov was designed with wobble built in to the piston attachment. It was screwed down tight then backed off 1/8 to 1/4 turn prior to being drilled and pinned. If the piston is rigid, it might jam things up when you beat the rust off the gun against a tree!

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