Bolt is jumping the rails

[spongejosh]

I just finished my first build and I have an issue. When the charging handle is pulled all the way back the left side of the bolt carrier pops up about 1/8" and the bold doesn't want to go forward unless I push down on it. It looks like the hammer is pushing up on the bolt and making the whole carrier lift.

It looks like a buffer would fix the problem but that seems more like a band-aid. Moving the rear trunion forward a hair would fix it but then I wouldn't be able to install or remove the BCG. What did I do wrong and how can I fix it? [Bang][Bang]

[lllRorlll]

hard to say without pics... id look at the pins and whatever you using for pin retention, if its not fully secured the hammer/trigger sits kinda higher-and goofy like until its fully snapped in

[gta_spec]

Unloaded of course, Try cycling it again with the trigger depressed so that the hammer is captured by the disconnector, not the trigger.

[zteknik]

What kind of reciever are you using?
The hammer pushing up on the carrier is normal,but it shouldn't jump the rails.
How does the carrier fit in the upper rails?Is it a snug fit or is it a bit loose?
Somtimes the upper rails get spread out a bit all they might need is just a slight pinch in a vice to snug them up.

If the carrier fits snug it sounds like the notch in the rear is a bit too big.you can move the rear trunnion foward a hair,and then file down the left rail a bit to get the carrier in and out.But that 's a bunch of work.
You would have to remove the rivits holding the trunnion in,weld up holes redrill,re reivit.
I would just run a bead at the spot on the left rail the carrier is jumping at and file down to fit.

Bring it over to Bert at BP Tactical and have him look at it.It would be an easy fix for him ;)

[Great-Kazoo]

Put the receiver cover back on and do it. I have a few FACTORY AK's that this happens to when the cover is off.

[spongejosh]

It gets stuck back just as much with the cover on. Testing it with the trigger pulled and the disconnector holding the hammer it hangs much less frequently. It's not fully jumping out of the receiver just enough that the left lug on the bolt seems to be lifting enough to catch on the rail and the recoil spring can't push it back. The cutouts on the rear of the rails are a nearly perfect fit to the bolt. Once it's locked back I can make it return by smacking the bottom of the grip so the BCG drops back down and overcomes the hammer pressure for a second. I'm using a Tapco G2 trigger with the parts kit hammer spring. The receiver is from Iron Hammer Armory and the rails are the same width from front to rear trunion.

I have a feeling it will shoot and cycle fine but I don't like the idea of it locking up on me if I pull the charging handle all the way back.

[spongejosh]

Here are the best pics I could get of it with my phone. This is the side that's hanging and these pictures are of it in the stuck state. Barely pushing down on the BCG at this point with release it and sent the bolt home.

http://i2.photobucket.com/albums/y24/spongejosh/Mobile%20Uploads/20130209_145037_zps84520bd7.jpg
http://i2.photobucket.com/albums/y24/spongejosh/Mobile%20Uploads/20130209_145352_zps4fdef881.jpg
http://i2.photobucket.com/albums/y24/spongejosh/Mobile%20Uploads/20130209_145417_zps9ab020d4.jpg

[bryjcom]

Its possible that the receiver cut out for the bolt carrier is a little large. The proper fix would be to weld up the top rails and then re-profile and fit again. I would use a tig welder.

You could be perfectly fine though. Sometimes when you pull the charging handle you will pull up a little bit was well and can cause that. During firing the bolt carrier could never have a problem.

I say run a couple of hundred rounds through it and then inspect the top rails of the receiver and see if the bolt carrier is hammering at the top rail. If it is I would weld it up, and re shape rails.

[lead_magnet]

^this

If you can fix it with a buffer then I say VIOLA! done.

[lllRorlll]

looks like a good build though, pics make me wanna fondle it

[brianakell]

Im going with it needs a new recoil spring. Carrier shouldnt be getting all the way back to rear trunnion when cycling, close, but this appears to be hitting and then popping up at the same time.

[lead_magnet]

looks like a good build though, pics make me wanna fondle it

I get that every time I'm in a locker room.