Yugo bolt/carrier hanging up

[shortround13]

doing test fitting before welding the rails, and just as the bolt carrier/charging handle reaches the rear of the trunion it is binding up. I've filed the ejector tip and checked for clearance, not that. put some sharpie on the bolt lugs to see where it was rubbing. Looks like the top of this lug is hitting in the trunion. thought initially the rails might be too high so stepped up to the next size bigger drill bit, didn't help, went all the way up to 9/32 just to see...didn't help the bolt to ride lower in the carrier to keep it from binding up.
is there a bigger picture that I'm not seeing (like with the receiver?) causing the bind that I need to remedy, or a little polish and shooting it in to help it loosen up?
also, 17/64 drill bit seemed to be the best size to line the rails up with the steps in the trunion.... there's not "hard and fast" rule about what size drill bit, it's just whichever gets the rails flush with the step right?

[Alex$]

Is it just the picture, or is the trunnion chewed up where you are pointing at it with the pencil?

[shortround13]

this kit looks like it has seen some use....yea not just the picture

[Alex$]

Check the underside of the trunnion, right where you are pointing with the pencil. Look for a raised bump, or dimple. Look near the end, close to the left side wall of trunnion.

Your bolt has a line scratched through the sharpie, or so the picture looks. That means there is a high spot on the trunnion, like a bump.

[shortround13]

The thing I'm curious about is that the bolt by itself moves freely in the trunion but when its in the carrier it seems to sit high....and then rubs the top

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[Alex$]

As you know, tolerances are loose, when in carrier some of the slop is taken up and the bolt rides where it should be.

Because the trunnion looks beat up and your bolt only shows wear in a single line, it would suggest that the part that is beat up is sticking down, as it were. If you have a dimple that is hanging down in the way, file it down and call it a day.

[baih777]

add some pics of the receiver.
did you have the center rivet in place ?

[shortround13]

Nothing is riveted yet.

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[yari]

The weld in rails need to be where the ejector rides in the groove of the bolt. It shouldn't have anything to do with why your getting binding. Rivit it together and then check the binding. Sharpe or dye them, and remove as necessary. Don't file anything till its built to its final state.

[ar15barrels]

doing test fitting before welding the rails, and just as the bolt carrier/charging handle reaches the rear of the trunion it is binding up. I've filed the ejector tip and checked for clearance, not that. put some sharpie on the bolt lugs to see where it was rubbing. Looks like the top of this lug is hitting in the trunion. thought initially the rails might be too high so stepped up to the next size bigger drill bit, didn't help, went all the way up to 9/32 just to see...didn't help the bolt to ride lower in the carrier to keep it from binding up.

is there a bigger picture that I'm not seeing (like with the receiver?) causing the bind that I need to remedy, or a little polish and shooting it in to help it loosen up?

also, 17/64 drill bit seemed to be the best size to line the rails up with the steps in the trunion.... there's not "hard and fast" rule about what size drill bit, it's just whichever gets the rails flush with the step right?

I have run into a few bolts that won't "go around the corner" well without a little clearance added on the non-critical front bottom corner where the lug meets the bolt body.
A very slight clearancing there has made significant improvements in locking and unlocking smoothness when I find this binding.

[shortround13]

Thanks guys. Good to know is a non critical issue, and good point about not doing any metal removal until all welded and riveted yari....will do (or not do in this case)

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