Bolt stick or something like that. [Archive]

Vomitsquad

03-17-2009, 05:49 AM

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

03-17-2009, 08:35 AM

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

03-17-2009, 12:46 PM

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

XM15

03-17-2009, 06:05 PM

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

03-17-2009, 07:04 PM

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

03-17-2009, 10:00 PM

From http://store.airgundesignsusa.com/index.cfm?fuseaction=catalog.prodInfo&productID=413&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

03-18-2009, 03:23 AM

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

03-21-2009, 05:22 PM

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

03-21-2009, 07:15 PM

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

Vomitsquad

03-22-2009, 03:00 AM

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.
:confused:

secretweaponevan

03-22-2009, 09:21 AM

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.
:confused:

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

03-23-2009, 03:01 PM

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

Vomitsquad

03-25-2009, 03:33 AM

secretweaponevan

03-25-2009, 05:29 PM

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

03-25-2009, 07:08 PM

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.

Vomitsquad

03-31-2009, 03:50 PM

Tried to increase trigger rod length about two full turns and now it works great. Aparently it was all from short stroking. Figure that.
I put the valve back on the Micromag it came from and it shot just fine so i figured it must be a trigger issue.

Thanks for all the help guys!

/John

athomas

03-31-2009, 04:16 PM

It is possible that short stroking invoked the bolt stick and that a trigger rod adjustment made that part of the problem go away. Even following a bolt stick, the bolt should reset. If it sticks and leaks air, even following a short stroke, you have a bolt stick issue. Until you find the actual cause of the sticking, the issue will crop up again when you least expect it.

Vomitsquad

04-01-2009, 05:06 AM

But the bolt didn't really stick. It whould be a more accurate description to say that it just didn't stay back after returning. Forward, back and then 1mm forward and hissing. Most of the times that is. Not always.
Doesn't that sound like a on/off problem?
Since it worked great untampered on the marker it came from it should just be the trigger differing, and not something in the valve/bolt, right?

athomas

04-01-2009, 05:49 AM

If the bolt does go all the way back before it comes forward, then yes that is not bolt stick. That is most likely an on-off problem, but not a trigger rod issue. The trigger rod does not affect when the timing between the on-off and the sear. If that is the case then you should be able to check it by holding the trigger back after a shot. If it leaks then you have an on-off problem. If it is not leaking/hissing when you hold the trigger after a shot and the bolt is forward, then it is bolt stick of some sort.