Yugo m70 cycling issues... HELP!!

[ZeroDistortionNow]

Ok, so I purchased this Yugo m70 Fixed stock AK-47 variant.. had it for about 4 weeks now, been to the range three times with it, fired it in my sand discharge bin a few times and spent all day messing with it and still no luck.

So here is the problem..

It will only fire one round at a time..

Now, here is what I have done thus far:

Checked to see if the gas port is correctly lined up and free from debris--- All good here

I have polished the botom of the bolt carrier to relieve drag

I have polished the entire bolt and cleaned till spotless

checked the gas piston for straightness--- All good here

I have polisher the striking face of the hammer for less drag

checked the recoil spring

the piston is tight in the carrier and only slightly rubs the top of the inside or the sight block pass through area

polished the ramps in the underside of the carrier where the bolt rides and turns to lock

polished the chamber area, feed ramp, trunnion sides, barrel breech, bolt lock lugs, firing pin

I have tried Tullammo, Wolf, Yugo surpluss, Silver Bear, Millitary Classic and custom hand loads from a friend. All with the same result.. It will fire the initially chambered round but it will not send the carrier rearward enough to pass the rear of the magazine to grab another round. I initially thought it was a drag related problem.. thus all the polishing, but now I am running out of ideas. It is a Century built product :( I have learned my lesson there.. won't buy another Century but I still need to get this one right

Please Help!!

[Schuetzenman]

Alright then. Sorry to hear of your problem AK. Tell me if you pull back on the charging handle and release it does the bolt group slam home? Next if you take a loaded mag and charge the weapon, if you take your hand and pull back on the charging handle will it eject the unfired case, then release the handle and will it seat another round?

If the bolt carrier stays back or will pickup and seat rounds when charged by hand you could have a binding problem. These are usually from gas pistons not being straight. BTW, they should be a little floppy, not rigid. Century welds them in and that works 99 times out of 100 but sometimes it causes an issue.

If it's not drag, then it's a lack of gas pressure on the piston. It could be there is too much clearance inside the tube around the piston head. I think this is a low probability cause, but it is possible to happen.

Lastly, you wouldn't happen to be using a recoil buffer would you? If so, take it out and try the weapon without it.

Lastly, welcome to Gunsnet.

[O.S.O.K.]

:welcome: to the board!

I would check a couple of things.

One - is the recoil spring original - correct for this model? You may try a new one to see if that's the problem - if it's short cycling then that may be it.

Does it cycle OK manually?

Is the fire control group installed properly? Is there any sign of a hang-up with that? Check schematics to be sure it is. If the hammer spring tension is too much, it can interfear with proper rearward travel.

Are the receiver rails allowing free travel? Take the fcg out and cycle manually without that in place - should slide easily back and forth.

Is the gas tube loose or rigid? If it's rigid, that may be the problem - it should be a little loose and allow the gas piston to move freely without any binding at all.

Likewise the gas piston should have a bit of wobble to allow it to move freely without binding...

That's about all I can figure - I'm not a Yugo owner and know more about standard AK's...

[Full Otto]

This is a little more than what I know about them. Does it have the folding grenade sight? I've read sometimes they cause problems by not sealing up properly when shut.
Just a guess though