Bolt stick or something like that.

[Vomitsquad]

I just put my X-valve to better use and therefore put this old Micromag AIR valve /w lvl7 on my ULE but i doesnt work very well. It's leak free but when pulling the trigger the bolt often sticks so you can see the front 2-3mm of it in the breech, hissing air down the barrel. If i pull the trigger a few times it usually goes back, but something is really badly set up here.

So what should i try first? Heavier spring?
Is there anything that needs to be adjusted triggerwise? (Benchy single trigger)

[chafnerjr]

I might get flamed for this one... I'm not a mag expert by any means, but check the bolt and sear to see if they are rough. I had an much less serious bolt stick issue that was solved by simply polishing the sear and bolt a little bit by hand. Seemed to fix me right up. However, I wasn't able to see any of the bolt in the breech. Seems like a much more significant issue then I was having.

Have you tuned everything else? Have you checked your FPS? I've seen people have these sorts of issues with their gun shooting at like 140fps... once they get up to the 220+ (really should be 280) everything is OK again.

[MANN]

check your detents first with bolt stick. lvl 7 bolts are wider than lvl 10

[XM15]

Does it have a power tube spacer? or does it have the old power tube spring? When the springs wear out they cause bolt stick.

[211]

check the frame and fieldstrip screws tightness
try loosening them up a little, and if that doesnt help or makes it worse, try going slightly tighter (not too tight nobody likes broken bolts or stripped holes)

[secretweaponevan]

From http://store.airgundesignsusa.com/in...&categoryID=18

The Spacer Kit gives you five different brass spacers, all legibly numbered so you can adjust the spacing of the power tube O-ring. If your gun has bolt stick, use a longer one; if it leaks down the barrel, use a shorter one. Find one that works and stick with it!

So use a longer spacer, or replace that old spring with a new spacer from a spacer kit.

[Vomitsquad]

Thanks guys! Having just a little spare time works wonders. Lacking even that, i'm lucky to have you helping me out. I think it's time for a thorough strip down and some polishing.
I'll let you know how i goes.

[Vomitsquad]

Tried it a bit more today and it shoots fine if i really over do the trigger pull. If i hold it down then it fires fine, bur if i pull the trigger quickly the bolt comes forward just a millimeter and leaks. Sometimes also when i release the trigger after firing.
It also seems to choke if i fire more than maybe 2bps.

Remedy?

[chafnerjr]

Have you adjusted the length of the trigger rod properly and checked the on/off?

[Vomitsquad]

I have never had to adjust a trigger rod so i'd really appreciate a quick how-to or alink to a thread explaining how it should be adjusted.

[secretweaponevan]

I have never had to adjust a trigger rod so i'd really appreciate a quick how-to or alink to a thread explaining how it should be adjusted.

With the safety on and marker gassed up, there should be a 1/16" gap between the back of the trigger and the tip of the trigger rod.

[athomas]

Have you replaced the bolt spring? An old worn bolt spring can cause bolt stick as well.

[Vomitsquad]

Replaced it with a brand new and slightly longer spring from a Mag parts kit, but nothing changed. As you can see a few posts up, the bolt doesn't stick that far forward, but something pushes it forward ever so little. I'm gonna check the trigger rod adjustment as soon as i get the time.

[secretweaponevan]

Replaced it with a brand new and slightly longer spring from a Mag parts kit, but nothing changed. As you can see a few posts up, the bolt doesn't stick that far forward, but something pushes it forward ever so little. I'm gonna check the trigger rod adjustment as soon as i get the time.

If it only pushes forward after gassing up, check for a worn sear, worn bolt lip, or messed up rail where the sear pin rests.

[athomas]

When you fire and hold the trigger does it leak any air out the front? It should hold air with the trigger held. Any leaking with the trigger held would indicate a leaking on-off top oring which could contribute to your problems.