Weird Sear Pin sticking issue

[athomas]

Pressure isn't the only factor on the reactive ability of the gun. The regulator has to have a high flow rate as well. The regulator on the 950 psi tank may have a higher flow rate than the 1150 psi tank. It may be better than the average tank, but still less flow than your 950.

[Mondoatx]

So... I got my new macro fittings in today and was dry firing in the backyard...

The gun is still doing it (sear pin sticking back periodically)... It does it less now that I changed out the RT on/off with the ULT on/off... but I am at a loss of how this is happening...

Thought it had to do something with the rt on/off... but since it is still happening after I changed to the ULE on/off it makes me think it is something else (king of the obvious over here)...

Happens MORE with the 1100 PSI tank... still happens sometimes with the 950... but not as much...

I tried going up a carrier size... and it leaked down the barrel.

I am no good with LX tuning... but it sticks forward and then you reach into the breach and shove the bolt back and the sear pin pops forward (most of the time... some times you push on it and it does not reset).

Let me know what you guys think (again).

Thanks as always.

M

[rawbutter]

Next time the sear gets stuck, degas the marker, take off the valve, and look at the little hole in the back bottom of the body where the sear pokes up to hit the on/off pin. If this is happening less with an RT on/off (which pushes back against the sear when resetting), then I'm betting the sear is actually sticking against the body itself, which is why it won't reset, even when you're pushing the bolt back. I've had one or two automags where the sear is just a tiny bit too big for that hole, or the body isn't aligned just right, and so it grabs the back corners of the sear and binds up.

Not sure why this happens. Automag tolerances are usually fantastic. But fixing it is easy, at least. Just grind down the back corners of the sear where it's hitting the body. You only need to take a tiny bit off the back edges, so you won't be changing how or when the sear hits the on/off pin.

[athomas]

You could have a leaking oring in your on-off top or possibly the small oring at the back of the regulator pin assembly. If either of those orings are leaking, you will get bolt reset issues.

[Mondoatx]

Next time the sear gets stuck, degas the marker, take off the valve, and look at the little hole in the back bottom of the body where the sear pokes up to hit the on/off pin. If this is happening less with an RT on/off (which pushes back against the sear when resetting), then I'm betting the sear is actually sticking against the body itself, which is why it won't reset, even when you're pushing the bolt back. I've had one or two automags where the sear is just a tiny bit too big for that hole, or the body isn't aligned just right, and so it grabs the back corners of the sear and binds up.

Not sure why this happens. Automag tolerances are usually fantastic. But fixing it is easy, at least. Just grind down the back corners of the sear where it's hitting the body. You only need to take a tiny bit off the back edges, so you won't be changing how or when the sear hits the on/off pin.

It is actually happening less with the ULT on/off than it was with the RT on/off... I will take a look at how the sear lines up with the body.

Thanks

[Mondoatx]

You could have a leaking oring in your on-off top or possibly the small oring at the back of the regulator pin assembly. If either of those orings are leaking, you will get bolt reset issues.

I am inclined to think it is not an o-ring in the on/off because it was happening both with the RT On/off originally in there and then still happening when I replaced it with the ULT on/off...

As for the reg pin assembly... I replaced those recently with new O rings... if it were leaking would I hear it?

[rawbutter]

As for the reg pin assembly... I replaced those recently with new O rings... if it were leaking would I hear it?

Yes, you could hear it, but if the problem is happening with both on/off assemblies, then you're right. It's probably something else like the sear sticking, or the field strip screw being too tight, or the reg seat o-ring.

[athomas]

I am inclined to think it is not an o-ring in the on/off because it was happening both with the RT On/off originally in there and then still happening when I replaced it with the ULT on/off...

As for the reg pin assembly... I replaced those recently with new O rings... if it were leaking would I hear it?

You wouldn't hear it if it was the oring at the back of the reg pin assembly. It causes a leak into the chamber the same as if the top on-off oring is leaking.

Another thing to check to see if the body pim is bottoming out in the rail. No matter how tight you got the body, it would never be ideal if this is the case. There have been some rails that had this issue but it was usually with the steel bodies more than the aluminum ones. It is something to check though. If it is too long, file it off a bit.

[Mondoatx]

Alright guys... got more air this morning... and some paint... added a shim to the ULT (because I am excessive - that's how I roll) ran through about 150 rounds in the backyard and probably that much dry firing... and no stick... so I am going to move on at this point and consider this solved...

Thanks for everyone's help.

If anything else around this comes up around this I will try the reg seat o ring and look at how the back of the sear interacts with the body... but for now I think I am good.

Thank you for everyone's help!! This thing is excessive (per my requirements/preferences) and people at the field tomorrow are going to pay the price (not noobs or renters though LOL).