How to replace gas piston "draft"

[KenR_RedStarArms]

GAS PISTON INSTALLATION INSTRUCTIONS

1.INSURE THE RIFLE IS UNLOADED AND REMOVE THE BOLT CARRIER ASSEMBLY FROM THE RIFLE.

2. REMOVE THE BOLT FROM THE CARRIER.

3. LOCATE THE 3MM DIAMETER CROSS-PIN (THE PIN SIZE MAY VARY BY COUNTRY OF ORIGIN) THAT RETAINS THE GAS PISTON TO THE CARRIER. IT MAY BE NECESSARY TO REMOVE THE FINISH FROM THE CARRIER IN ORDER TO LOCATE THE CROSS-PIN ENTRANCE AND EXIT HOLES IN THE CARRIER. THE CROSS-PIN IS NORMALLY ABOUT LOCATED ABOUT 7MM (.28”) FROM THE FRONT EDGE OF THE BOLT CARRIER AND RUNS IN A HORIZONTAL DIRECTION.

4. USE A NAIL SET OR DRIFTPUNCH TO START THE CROSS PIN MOVING AND A DRIFT PIN PUNCH TO DRIVE THE PIN THRU THE HOLE. IF EXCESSIVE FORCE IS REQUIRED TO DRIVE THE CROSS-PIN OR IF THE CROSS-PIN REFUSES TO MOVE, CENTERPUNCH ONE END OF THE CROSS-PIN AND USE A 3MM DRILL BIT TO DRILL .10” DEEP INTO THE CROSS-PIN. DRIVE THE CROSS-PIN OUT FROM THE SIDE YOU HAVE DRILLED.

NOTE: THE CROSS-PINS ARE OFTEN PEINED INTO COUNTERSUNK AREAS ON THE CARRIER. WHEN DRIVING THE CROSS PIN OUT IT IS NECESSARY TO DISPLACE THIS METAL BEFORE THE PIN WILL MOVE.

5. CHUCK A 3MM DRILL BIT INTO A DRILL PRESS AND INSERT THE BIT THRU BOTH HOLES IN THE BOLT CARRIER WITH THE BOLT CARRIER HELD LOOSELY IN A DRILL VISE. USING THE DRILL BIT TO POSITION THE BOLT CARRIER, TIGHTEN THE DRILL PRESS VICE SECURELY AGAINST THE BOLT CARRIER.

6. THREAD THE RED STAR ARMS GAS PISTON INTO THE CARRIER. IT SHOULD SCREW IN USING ONLY THE HAND. A 1/8” DIAMETER OR SMALLER STEEL ROD, INSERTED THRU THE CROSS HOLE IN THE GAS PISTON’S HEAD, MAY BE USED TO ASSIST IN THREADING THE GAS PISTON INTO THE BOLT CARRIER. IN CASES IN WHICH THE FEMALE THREAD OF THE CARRIER HAS BEEN DAMAGED BY THE REMOVAL OF THE CROSS-PIN A 12MM X 1.25MM TAP SHOULD BE USED TO CHASE THE THREADS.

7. DRILL THRU THE GAS PISTON USING THE 3MM DRILL BIT ON THE SAME LOCATION AS THE TWO 3MM HOLES IN THE BOLT CARRIER.

8. INSERT A NEW 3MM CROSS-PIN INTO THE HOLE. THE CROSS PIN SHOULD BE LONGER THAN THE HOLE IS DEEP, AND EXCESS STOCK SHOULD BE POSITIONED EQUALLY ON BOTH SIDES OF THE BOLT CARRIER. USE A HAMMER AND PUNCH TO PEIN THE ENDS OF THE CROSS-PIN INTO THE COUNTERSINKS ON BOTH SIDES OF THE BOLT CARRIER HOLE. DRESS THE ENDS OF THE CROSS-PIN FLUSH WITH THE SURFACE OF THE BOLT CARRIER.

[7.62x39]

Are you saying that the piston should be screwed all the way into the carrier?

Every kit I have seen, has had the piston backed off about a half of turn.

I was under the impression that this was the correct installation, and that the piston should have a certain amount of movement, when properly installed.

[NewtoFals]

Every chinese ak i have seen has the gaspiston screwed in all the way. NO slop.

[Packrat]

I've seen both. Usually they say to back it out 1/4 turn. If it's
screwed all the way in, there's no flexing, so everything must
be properly aligned. If there's a little flexing it allows for some
misalignment. I've never had trouble with a bolt carrier with the
piston screwed in tightly.

[KenR_RedStarArms]

We have done it both ways. I had a ratty t-hole sar-1 welded piston. Cut it loose installed new piston; no pin nothing shot 500 rds through it. No movement nothing it worked great. Then we drilled and pinned it. I have used loctite; jb-weld and tig welded them rascals. They all shot. Now how accurate where they? Believe it or not very little was noticed on the 7.62x39 guns they just keep chugging away 1 1/2 2 inches at 50 yds pretty normal from the shoulder. No failures to cycle or feed. And no we do not clean them at all. We wanted the system to be robust and work and if it was going to get cleaned it was going to have to do it itself.

We are always looking and learning about the AK system. I get a lot of letters from AK owners and they share there knowledge and wisdom with us. It is like have a 100 field testes all the time. And some of the shooters have some great ideas about the next tactical concept for the AK.

It is a great time to own an AK.

To answer the question both ways work or as the girl said
"we have both kinds of music, country and western"

[CAMPYBOB]

to slop...or not to slop...that is the question!

here's the deal.

if you hand tighten (notice i didn't state, "use the big freakin' wrench.".) the shoulder of the piston against the carrir's face and pin it you will have a little slop soon enough.

all it takes is some shooting to develop some clearance between the parts. voila! instant slop.

some ak manufacturers build in a little movement from the get go. others do not. with the clearances built into the rifle already, the choice of whether to slop or not slop is up to the individual builder.

[allesennogwat]

If you drill to 1/8 inch you can use an 1/8 inch roll pin like the Valmets and Galils use.I changed my non chrome plated Valmet 71 gas piston to a Bulgarian chrome plated take-off piston.I had to increase the original hole in the Bulgarian piston to 1/8 inch to use the original Valmet roll pin which was a perfect fit in an 1/8 inch hole.

[wolfkidd]

This is *very* useful information: I had been wondering about it, since I had previously noted that Galil pistons were roll-pinned in place.

Wolfkidd


If you drill to 1/8 inch you can use an 1/8 inch roll pin like the Valmets and Galils use.I changed my non chrome plated Valmet 71 gas piston to a Bulgarian chrome plated take-off piston.I had to increase the original hole in the Bulgarian piston to 1/8 inch to use the original Valmet roll pin which was a perfect fit in an 1/8 inch hole.

[gaucho1]

I saw campy's post and though he's back.
Then I saw the post date......