One for the Pros to venture forth on. XMT Body not getting into the rhythm.

[XtraKargo]

Hey all,

So I have recently gotten an XMT ULE with the Classic RT look, for an X-valve. When I had the Valve in the original AGD ULE body, it was a perfect, walkable, rhythm to the trigger. Once I dropped in the XMT Body, it catches on the return briefly. Then resets, and is able to fire again.

SOOOOOO, I tried my classic valve from a Minimag. Shoots fantastic in the XMT Body. Then I had to test the X-Valve and finally gotten it back to perfection in the AGD ULE with no shims in the LVL10 using a 1 carrier, gold spring and lubing everything once again. I have the Thumb screw finger tight only (in the AGD ULE I would put the 1/4 turn on it) A mag whisperer once told me to try adjusting the Thumb screw slightly with different aftermarket parts. No luck here.

So here is a short Video. And my open mind looking for insight. Thanks folks.

[BigEvil]

Do you have the correct front frame screw and rail bushing in there? Also, try tightening up the thumbscrew with an allen wrench.

[XtraKargo]

Same screw that came from the AGD ULE body and the bushing is there as well.

If I tighten the thumbscrew it is the same deal.

(By the by - you were the Mag whisperer, thanks)

[need4reebs]

with the body off the rail try dropping the bolt into the body to see if it will fit into the breech...you might have a bur somewhere around the breech...a lil needle file and a few minutes should take of that if you have a bur.

[XtraKargo]

with the body off the rail try dropping the bolt into the body to see if it will fit into the breech...you might have a bur somewhere around the breech...a lil needle file and a few minutes should take of that if you have a bur.

Drops in clean. I even removed the detents during the video, they shown some where but the body is clean inside.

[nak81783]

When you say it catches on the return, do you literally mean the bolt is slow to spring back, or do you mean it just recharges slowly?

If the distance from the center of the rear field strip screw to the bolt spring seat inside the body is different (it can vary significantly even from one AGD body to another), you may need to tune the Level 10 to that particular body. Perhaps the distance is longer, so you need a longer spring than the gold one you indicated you are using. Are you using the largest carrier that doesn't leak? If not, this hypothesis holds more water, as bolt stick with a weak spring (for the longer distance anyway) is more likely.

Are you using a ULT? That may need to be tuned for a specific body as well. Slowly add shims to see if that helps.

I haven't done a pneumag (yet). Is the ULT required to help it cycle at a lower lpr setting?

[XtraKargo]

It is strange, it returns quickly, then pauses for a short period, and clicks into place.

There isn't a ULT involved, but it is a pneumatic trigger. Very light trigger pull and easily walkable.

I will double check my carrier to O-ring again for leaks. Just to be certain.

[BigEvil]

Crank your velocity way up and keep firing it. See if it goes away after a while and then lower your velocity to normal. Ive seen similar issues on new Xmag breeches. You would see some wear on the inside where the bolt would rub slightly. Once you saw where it was rubbing, you could polish it out with some emery cloth.

[nak81783]

What is the bottom wall thickness of the working vs. non-working bodies?

What length on/off pin are you using? If .750", humor me, and try a .712" if you have one.

Edit: I should say I don't expect the shorter pin to fix the issue, although if it does great. I would rather like to know if it gives a different result - barrel leak, bolt never resets, etc. On the rare chance that you have a .765" pin, try that one too, and let us know what it does.

[nak81783]

Crank your velocity way up and keep firing it. See if it goes away after a while and then lower your velocity to normal. Ive seen similar issues on new Xmag breeches. You would see some wear on the inside where the bolt would rub slightly. Once you saw where it was rubbing, you could polish it out with some emery cloth.

Would it be advantageous to do this with a Level 7, if available, to really beat things into submission?

[XtraKargo]

Now I don't have a set of digital calipers, but my old ones show it as just shy 1/16th, and they both are the same, the calipers slides right off of one and onto the other. With the carrier I stepped up to 1.5 and it leaked so I went back to a 1. (granted this is a fresh o-ring to, in my troubleshooting on my own, I figured why not, to see what happens without shims and where I end up on carriers. really was good refresher on the LVL10 also.) I would venture to say this one is a .750 since it just touches the 3/4 mark. I will have to pull my Retro Valve out of storage to see if it is different or not.

With the Velocity turned all the way up it still sticks, and it appears to rub on the upper portion of the body where the outer rim of the bolt pushes against the top (that is the only part that looks scored, but mildly so, a darker grey color). The breech still looks clean. I wondered about the LVL7 myself, if it would make a difference.

[XtraKargo]

Also with that guy turned up it gets LOUD! HA

And just for good measure I tried the longer spring.



With the velocity turned up I blew out my foamy, so I will get the joy of replacing it later as well.

[nak81783]

Is the rubbing along the entire stroke, beginning only, end only?

Oh and to clarify, when you put your classic valve on the XMT body, was all that still the pneumag rig, or did you put the XMT body on a standard Mag?

I'll do some tinkering tonight to see if anything else comes to mind. Would still like to know what a different pin length does if you can find one.

I just blew my first foamie off (that I can remember) recently when tinkering with RT effect. Loctite Ultra Gel seems to be working well. Works well on the bumpers too. It's cheaper and easier to find than Loc-Tite 380 or IC-2000, but it has the same rubber toughened, impact resistance properties. I used a dental pick to scrape off the old adhesive. It snaps off in flakes. I also then scuffed up the parent metal and cleaned it with wifey's nail polish remover. Seems to be holding well.

Edit: My X-Mag and ULE bodies have rub marks inside the top of the body near the spring seat. Just an FYI, as the degree to which your marker is rubbing may be different.

[XtraKargo]

I just blew my first foamie off (that I can remember) recently when tinkering with RT effect. Loctite Ultra Gel seems to be working well. Works well on the bumpers too. It's cheaper and easier to find than Loc-Tite 380 or IC-2000, but it has the same rubber toughened, impact resistance properties. I used a dental pick to scrape off the old adhesive. It snaps off in flakes. I also then scuffed up the parent metal and cleaned it with wifey's nail polish remover. Seems to be holding well.

Thanks for the tip!

I tried a Minimag rail and the XValve and got the same thing, but my most recent postings have been with the Pneumag setup.

I would guess it to be the end, or return it is scuffing, but this is minimal at best. It is only directly above the Sear Slot, and doesn't look roughed up. The detente with the smaller/thinner o-ring was fairly chewed up. This doesn't look like that.

[nak81783]

So the problem follows the XMT body and X-Valve? Without those two together, everything works as it should? Am I understanding that correctly? Does the classic valve have a Level 7 or 10?

Also, when asked about the front frame screw, you said it's the same as the one you used on the ULE body. However, is it snug? If so, make sure the head is securing everything together. In other words, make sure it didn't bottom out, and the head isn't able to snug up to the trigger frame. If this is the case, put a washer between screw head and trigger frame, and see if that helps.

[XtraKargo]

They seem to be the only two with symptoms.

The frame screw is one that I doctored a while back to make sure the fit correctly in my AGD ULE body. I sanded the threads down some, and then on some of my projects I have had to make sure the Rail and the Body fit snug at the front and back. So the fit on the XMT to the rail is tight.

I can cater to some testing, even thou it is limited to what I have. There is a Minimag that is pretty much stock. And another twistlock style mag with a retro valve. Mostly Eclipse splash parts except for the SS body.

I can just hammer the body with the X-valve for a while as well and see if it gets better. I haven't moved the LVL7 to the X-Valve yet.

[XtraKargo]

Crank your velocity way up and keep firing it. See if it goes away after a while and then lower your velocity to normal. Ive seen similar issues on new Xmag breeches. You would see some wear on the inside where the bolt would rub slightly. Once you saw where it was rubbing, you could polish it out with some emery cloth.

How many shots you thinking, cause eventually my wife will want to shoot me with it from all the racket...

[XtraKargo]

So the problem follows the XMT body and X-Valve? Without those two together, everything works as it should? Am I understanding that correctly? Does the classic valve have a Level 7 or 10?

Tested this morning and here is the sequence of events.

Removed the Classic Valve from the Minimag - inserted the X- Valve - tested fine.
Removed the Minimag Body and twistlock pin - set the XMT Body on - inserted the X-Valve - FIRED A SINGLE SHOT AND FROZE... Trigger has pressure, and the bolt returned and stopped.
Removed the X-Valve and inserted the Classic Valve - tested fine.

This was all on the standard mag rail - with a standard sear - no pneu involved.

Just posting this for food for thought. (I have yet to measure the Retro Valve pin.)

[nak81783]

Good information.

Still need confirmation if Classic valve has Level 7 or 10, please.

Was that single shot intentional, or did it do that when you first aired it up (regardless if you were holding the trigger back upon airing up)?

When froze and the trigger still had pressure, was the gap between the trigger rod and back of trigger what it normally would be (typically credit card thickness), or was the gap larger (i.e. was there only trigger pressure towards the back of the trigger pull?

[XtraKargo]

Good information.

Still need confirmation if Classic valve has Level 7 or 10, please.
LVL7 - truly classic.

Was that single shot intentional, or did it do that when you first aired it up (regardless if you were holding the trigger back upon airing up)?
It was intentional, I didn't hold the trigger down when airing up.
When froze and the trigger still had pressure, was the gap between the trigger rod and back of trigger what it normally would be (typically credit card thickness), or was the gap larger (i.e. was there only trigger pressure towards the back of the trigger pull?
No it was larger, and rather than change the sear pin length, I used a small allen wrench to fill the gap and tried again to fire. No luck.

Thanks again for checking in on this one.

[nak81783]

Well, let's continue to isolate variables. On the std rail/sear, non-pneumatic setup, and XMT body, try the following:

1. Put the Level 7 in the X-Valve. What happens?

2. Put the Level 10 in the Classic valve. What happens?

3. Put the RT on/off assembly in the Classic valve. What happens?

4. I've never done this, so think it through first. Put the Classic on/off assembly in the X-Valve. What happens? I don't remember what the different pieces to the Classic on/off are made of. Worst case I can think of is you get a few scratches in the on/off hole of the X-Valve, but the orings and careful installation should prevent this.

[XtraKargo]

Here goes.


X valve with LVL 7 froze. Not a single shot.

Classic with the lvl10. Cycled fine.

Bolts left alone from here on out.

Classic with lvl10 and rt on off. Back to the same as the video. Cycles and pauses before reseting.

X valve with level7 and reactor on off (I don't think I have a stock On/Off to the classic, and this dropped right in) leaked down the barrel but cycled as fine. Almost as fast as I could pull a mech trigger.

[nak81783]

What are the lengths of the RT and Reactor pins? It's OK if you don't have calipers. Just lay them side by side, and if there is any difference whatsoever, tell us which is longer how many Level 10 shims it takes to make up the difference in length.

Also, on the RT pin, what's the length of the head (as closely as you can measure with whatever measurement tool you have)?

Oh, and I can't get the video to work. It just takes me to some pictures on photobucket. I tried it on my iPhone and two computers.

[XtraKargo]

What are the lengths of the RT and Reactor pins? It's OK if you don't have calipers. Just lay them side by side, and if there is any difference whatsoever, tell us which is longer how many Level 10 shims it takes to make up the difference in length.

Also, on the RT pin, what's the length of the head (as closely as you can measure with whatever measurement tool you have)?

Oh, and I can't get the video to work. It just takes me to some pictures on photobucket. I tried it on my iPhone and two computers.

Looks to be the same to me.

[OPBN]

Looks to be the same to me.

Is it just me or does the pin on the left look bent?

[nak81783]

I'm guessing that's an optical illusion. Plus, it cycled in the Classic valve, which is exerting less force than the X-Valve. I would think any binding from a slight bend wouldn't have worked in the Classic valve.

Open up the two halves of the RT on/off assembly. Anything inside that shouldn't be?

[XtraKargo]

It seems to lean some when stood on end. Maybe it is but it does seem to line up and do the job.

[XtraKargo]

I'm guessing that's an optical illusion. Plus, it cycled in the Classic valve, which is exerting less force than the X-Valve. I would think any binding from a slight bend wouldn't have worked in the Classic valve.

Open up the two halves of the RT on/off assembly. Anything inside that shouldn't be?

Not really. It looks good to me. The bottom has some wear on the outside. But nothing major.

[OPBN]

The RT in the classic had issues as well as in the X. On/off seems to be the culprit. Where the shaft meets the larger section looks bent.

[nak81783]

You're right. I didn't thoroughly read the answers to my own questions. Good catch.