Frame has to be loose to fire!?

[warbeak2099]

Ok, I'm still trying to break my custom ULE mag in. I'm having to untighten the front frame screw and the field strip screw in order for the gun to be able to fire. However, I have to untighten them so much that the frame and the body wiggle around. The gun shoots great, I love it and all but it's sloppy. I don't like that the frame and body are moving around like that. What can I do? Coolhand said that if I tighten the screws too much it will actually bend the body and that's why it wouldn't fire before. Well now it fires but the body and frame are swimming around lol. I know I haven't put 2500 shots through it. I've put about two tank fulls through it and not all the shots were with paint. Bout 1600 shots been put through it and probably 1000 of that was with paint. Do I just need to break it in a little more? The thing is, when I tighten it just enough so that the frame and body don't move around, the bolt sticks and it won't fire. When I loosen the screws it fires great but the gun wiggles. Is this normal, is my baby going through a phase?

Thanks,
Pete

[space_weazel_45]

[Dryden]

I've been reading suggestions similar to this for about six months and have to say that I don't buy this frame tension theory. I accept the fact that the marker might work better or worse because of tightening or loosening the frame and field strip screw, but that this would have anything to do with deforming the body doesn't sound right. If anything would deform the aluminum body, I would think that a bolt slamming around inside of it at 100mph would be the culprit, not a little bit of torque on an allen key.

Check your on/off assembly and on/off pin length, or in the case of the ULT adjust the number of shims (which has the same effect of adjusting the pin length). Tightening or loosening the frame screws alters the top of the sear in relation to the bottom of the on/off pin. You should get the same result by fully tightening both screws and shortening the ULT (add shims).

[CoolHand]

Do not underestimate the leverage generated by a machine screw (or any threaded fastener for that matter).

The bolt and spring are working in line with the body, which will produce no bending at all (by themselves anyway). But the field strip screw and the frame screw are working perpendicular to the body, which when coupled with the force from the bolt spring will induce a bending moment in the body. This is what (I suspect) is deforming the body (if it is indeed deforming).

I have heard of and seen many markers with this same malady, with nearly every combination of rails, bodies, and frames there is, and loosening the screws and retorquing them to match fixed >90% of the afflicted markers. (That is not to say that they should be so loose that the frame moves around though.)

Why does it work? I don't have any concrete proof, but I suspect that the bodies are just a little under engineered, and that given the right set of circumstances (bolt spring a little too long/stiff, body alum just a little thin or a tiny bit weak, all the frame, rail, and valve tolerances stack up in one direction, etc.) the bolt will bind and cause the marker not to fire. Look at the cross section of the ULE bodies verses the SS ones. The ULE's are not significantly thicker, yet the material they are made from (7075 T-6 alum I'm guessing) is only 1/3 to 1/2 as strong.

Now, I agree that the SS bodies may have been over engineered, but when over half of the stiffness is lost due to a change in material, a change in design is almost always required (which was done to some extent). What we have here is a near direct port from one material to another, with a quick numbers check to be sure that the rigidity came right to the minimum required. Which is fine (that's what great engineers do), but when you walk on the razor's edge, sometimes you get cut.

I must admit though, that I am not set up properly to measure and prove that what I have just postulated, is what is indeed happening. As usual, I could be totally correct, or I could be completely full of crap.

Now that I have said all of that, Dryden's notion that the screw tension is altering (by some means) the On/Off pin length is an intriguing point.

What made me lean towards the overtightened screws was the fact that he used a different valve with the ULT from his valve in this marker, and everything worked just fine. That tidbit pushed me to suspect the screws, and an out of tune Lvl X, working in conjunction to screw him.

At any rate, we'll get your marker squared away, one way or the other.

[warbeak2099]

Ah, sorry bout that I forgot to mention that bit. Yes someone else let me use their x-valve. When I put my ULT in their valve it worked fine. My ULT is set-up just fine. I will try tightening the front frame screw enough so that the frame and mainbody remain stable and then I will adjust the field strip screw accordingly as space_weazel_45 suggested. If that does not work well, I'm stumped. I'm 99% sure it has to be the tension though, since when I tighten the screws the gun won't fire and when I untighten therm it fires great. It has to be that. I'll try adjusting the field strip screw according to the front frame screw though. That sounds like it may work. Thanks everyone. Any other suggestions/comments?

[eNder159]

hey could it be possible that warbeak might have OVER torqued the frame screw causing a permanent bend in the aluminum body?? ..because when i had a look at it...it was pretty torqued in there...and had to loosen it back up with a significant amount of torque...so im wondering..maybe it was so over torqued that maybe coolhands frame/rail/ or even the ule body might have made a .1 or even a .01 out of tolerance?...could that possibly be his problem?...

[awn93076]

Something that I have noticed on a few automags with this problem:

Grip is held on be the field strip screw in the back and usually a 10-32 steel button head screw in the front. Take out your barrel, tighten up both screws and take a look inside from the front of the body. Can you see the tip of the front screw protruding into the body?

A lot of the time, either due to a physically fatiqued grip, or to a replaced screw that is a little long, you can have problems. The front screw pushes against the bottom of the barrel and when you pull the trigger, the bolt can't fit into the bore.

If that is the problem trim off your front screw and you should be good to go.

[warbeak2099]

There is no hole in the body for the front screw to come up through. ULE bodies are supposed to be like that right? Maybe I should trim the screw anyways? And how would I trim the screw? I'm no good with tools or anything. I don't even own a dremel.

[sqlloser]

Not really familiar with the ULE body myself. AWN was making reference to a normal classic body. What AWN was describing is not your problem. ULEs have screw on barrels instead of the classic automag locking barrel so the bolt wouldn't get jammed by a maligned frame screw on your marker.

Don't go off shortening any screws either. It's hard to diagnose a problem without acutually seeing your marker. Dig up the yellow pages and see if any of the local shops has somebody that knows automags. Although they will certainly charge you to work on it, most places give advice for free.

[Tunaman]

Youy dont say what frame/rail you have on there. Is it stock AGD stuff? :)

[warbeak2099]

Here's the kicker, it's a Logic Vert Frame and Alpha Rail. Also, my local pro shops don't have any AGD techs. The closest I have to that is a guy who took an AGD tech class in 1992. I do notice that when I gas the marker up the frame, rail and body do tighten up under the air pressure. There is still a little bit of movement though. Might I have an imperfect rail or frame from Coolhand?

Oh, I almost forgot. The ULE body was re-annodized a lighter blue. Might the ano have thrown off tolerances like powdercoating does?

Thanks all,

Pete

[Chronobreak]

tighten both the front and back frame screws to the same "tightness"

[BlackVCG]

I agree with shaving down the front frame screw. If it's too long, it can push against the bottom of the body and cause an alignment issue. If you can, find some washers to put on the screw or use a grinder to shave down the end of the screw a bit.

Once you get the front frame screw shorter, fully tighten it with an allen wrench and then insert the valve and tighten it by hand to start out with and then try tightening it up a bit more with an allen wrench and see how it shoots with both settings.

[CoolHand]

Here's the kicker, it's a Logic Vert Frame and Alpha Rail. Also, my local pro shops don't have any AGD techs. The closest I have to that is a guy who took an AGD tech class in 1992. I do notice that when I gas the marker up the frame, rail and body do tighten up under the air pressure. There is still a little bit of movement though. Might I have an imperfect rail or frame from Coolhand?

Oh, I almost forgot. The ULE body was re-annodized a lighter blue. Might the ano have thrown off tolerances like powdercoating does?

Thanks all,

Pete

Its not the body, the rail, or the frame, as all those parts worked just fine with the other guy's valve. It would be very odd, if they were causing the problem, but only with the one valve.

I know the bolt tension thing seems like smoke and mirrors, but untill we can narrow down exactly why it has an effect, you may just have to be happy that it fixes the problem.

There are so many variables at work here, that it the problem becomes almost too complex to tackle (or so it seems). I have seen markers with this problem in every configuration you can think of, with the only parts in common between them all being an AGD ULE body, RT valve (of some kind, be it RTP, EMag, or XValve), and the Lvl X kit installed.

It would seem to me, that the cause would lie somewhere in the common parts, either by dynamic interaction (one part moving incorrectly, pushing another out of line, etc.), or by some simple cause/effect system that we haven't as yet identified (frame screw a fuzz too long, On/Off pin incorrect length, body slightly bent, etc.). However its happening, the problem almost has to be in the parts common to all the markers afflicted.

If we start to keep track of all the markers that come up with this problem (specs, use, care given, abuse, etc), then we will eventually narrow the field of possible causes down to a point where we can say Ah Ha! Its _______ that's causing this!" Then we can work on fixing whatever the blank happens to be.

[eNder159]

for now...whatever works works...and leave it at that..until something more specific cna be found..

just keep messing with the field strip screw and the front frame screw...i believe i remember somebody saying that the torque being applied on the two screws has to be the same..