ULT on/off

[maineiacpballer]

So this is suppose to separate to allow shims to be added and removed, but how much play in the two pieces should there be when it is screwed back together?

I am trying to work on someones gun, cause I know more about mags than he, but I am lost with this. After screwing the two halves back together are you suppose to be able to separate them without unscrewing them? Not to have them become two separate pieces, but so that a gap is able to exist?

[maniacmechanic]

So this is suppose to separate to allow shims to be added and removed, but how much play in the two pieces should there be when it is screwed back together?

I am trying to work on someones gun, cause I know more about mags than he, but I am lost with this. After screwing the two halves back together are you suppose to be able to separate them without unscrewing them? Not to have them become two separate pieces, but so that a gap is able to exist?

The simple answer is yes , you would think it is " broken " , it screws together " loose "

[maineiacpballer]

The simple answer is yes , you would think it is " broken " , it screws together " loose "

So why when installed and then the gun is aired up you hear the sear set, but then pull the trigger and nothing happens?

[maniacmechanic]

So why when installed and then the gun is aired up you hear the sear set, but then pull the trigger and nothing happens?

How close is the trigger rod to the trigger when aired up ? should be about the thickness of a credit card

[athomas]

If the front chamber is charging and the sear is released, the gun will fire, regardless of whether the on-off is working. If the on-off is not working, you may not get another shot off though due to on-off induced bolt stick. That being said, if the bolt had enough air available to push it forward against the sear, it should fire if the sear can release it.

If the on-off is pushing down on the back of the sear but does not not open to allow air to flow, the front chamber will never charge with air. The bolt will not move forward when you pull the trigger. This is usually an indication that the on-off pin is too long or that there are not enough shims installed in the ULT. Add enough shims to the ULT to allow air to flow when the trigger is released but not too many that will cause the on-off to open before the sear is rotated far enough to hold the bolt. Each setup is slightly different due to tolerances, but the general consensus is that around 3-4 ULT shims should be used. Each ULT shim is 0.005". Each level 10 shim is 0.010". Be aware of the difference in thickness in case you get them mixed up.