AK74 help needed -- bolt stopped rotating w/ round -- pics added

[cens]

I have an AK74 that worked like a champ for over 500 rounds but then the bolt suddenly stopped locking on a round. With no round in, everything cycles smoothly -- the bolt rotates into locked position without any trouble. Once there is a round in the chamber, though, the bolt refuses to rotate the final quarter inch or so into full lock (and the bolt is a pain to pull back out).

Here is what I think I have ruled out:

--The gun is put together correctly
--The barrel is not blocked (rounds go in cleanly by hand)
--I am not riding the handle down
--There are no apparent burrs on the rails
--Lubrication is not an issue
--The bolt seems to be OK and is clean
--The piston moves freely
--Ammo or magazine issues

Any suggestions on what else I should look for?

Thanks!

[TOrrock]

What make and model is it?

If it's a kit built onto a receiver, what receiver, what kit, condition of kit, and who put it together.

Sounds like your headspace could be off.

[cens]

What make and model is it?

If it's a kit built onto a receiver, what receiver, what kit, condition of kit, and who put it together.

Sounds like your headspace could be off.

Bulgarian parts on a NODAK Spud receiver. Condition of the parts is good. I bought the gun used so don't know who put it together. Whoever did, however, had it so it was running flawlessly when I got it. Would head space go "off" if it was on for hundreds of rounds?

Regards,

Chris

[bvmbandit]

What do the trunnion rivets / screws look like under and around the outside of the heads? Remove the carrier and put a spent case in the bolt, run the case into the breach and see if the bolt locks completely. This will be harder to do with a spent case. Re- install bolt into carrier and try the same with a spent case. What do you find? Once the bolt is completely locked in place with spent case / snap cap does it unlock smoothly? Remove the bolt and run the carrier from front to rear on receiver. How much side to side play does the carrier have on the receiver slide rails through the entire length of travel? Where does the side play change at what position on the rail? Check the ejector. Has it moved up or down as it should be completely straight? Do all of this without a magazine in the rifle. Let us know what you come up with and go from there. Eliminate one factor at a time and you'll probably find what's going on.

HTH,
Scott

[Iraqgunz]

I am confused. In your initial post you state that it is assembled correctly, and make other absolute statements. Then this post you say it is used, you don't know who assembled it, or anything else.

Do you see the problem here? Parts guns (especially AK variety) tend to be problematic and I am sure that Templar and others can validate that. Some run good, others don't.

My guess is that something has gone out of spec. Whether it be the receiver (flexing?) or possibly burrs on the bolt or chamber area.

I am far from an AK expert but I have worked on a few hundred or so.

Bulgarian parts on a NODAK Spud receiver. Condition of the parts is good. I bought the gun used so don't know who put it together. Whoever did, however, had it so it was running flawlessly when I got it. Would head space go "off" if it was on for hundreds of rounds?

Regards,

Chris

[oddballmkg]

Have you checked to see if you have the forward section of a split case still stuck in the camber?

[cens]

Thanks for all the suggestions -- much appreciated.

bvmbandit -- I will run through those tests next weekend (I'm away from the gun right now).

Iraqgunz -- My absolute statements about the assembly are based on the fact that the gun worked very well for 500 rounds and all the parts are in the same place. I didn't mean to suggest that something could not have gone out of spec. Other statements just address what I have observed. I haven't found any burrs along the rails or where the bolt rotates closed.

oddballmkg -- I spent a fair amount of time with a good light and a probe looking for case shards in the chamber area. I was hoping to find one but no luck.

[cynical]

Does it properly extract and eject? Or does the bolt not close enough for the extractor to grasp the case? Is it possible the extractor is broken and/or has something wedged underneath it?

[cens]

Does it properly extract and eject? Or does the bolt not close enough for the extractor to grasp the case? Is it possible the extractor is broken and/or has something wedged underneath it?

When I have unstuck the bolt from its not quite fully locked position, the bolt opens with some violence and the round flies out like it has been ejected. I need to check if I can see how the extractor is holding the case when it is partially closed. I have cleaned/reinstalled the extractor, but I do not know if it is tensioned appropriately.

[Peshawar]

From what I can tell by your description, it sounds as though the headspacing has changed. You probably don't have a set of go and no-go gauges, do you?