Automag problem (first shot hot?)

[superman]

I wonder if it isn’t also the reg piston.

[rawbutter]

I wonder if it isn’t also the reg piston.

I always thought that the regulator piston was just a safety feature that vents if the internal pressure gets too high. If it's broken, then it just wouldn't vent when over pressurized, right? Or it would vent all the time? I don't think it would cause any velocity spikes. That's controlled by the regulator springs and the back cap.

[superman]

facepalm you are correct. been one of those weeks. you changed the reg seat oring on the reg pin right?

[nak81783]

Reg springs push on reg piston which pushes on reg pin. They work as a system.

http://www.zdspb.com/media/tech/animations/rtemag2_15fps.gif

The reg piston needs to move freely and consistently just like the reg pin. They are in constant (or almost always constant) contact. If the reg piston doesn’t move freely, it can cause velocity issues. Same potential issues, debris, “bad” (e.g., too large, but not leaking) o-ring, etc.

This statement is independent of the reg piston’s internal overpressure safety feature.

[rawbutter]

I changed the reg pin o-rings, but I think I forgot to change the seat. I'll do that when I replace the springs. I can replace the o-ring around the reg piston too.

[rawbutter]

The saga continues....

I got my spare parts in yesterday. I'm replacing the red bolt spring and the inside regulator spring. (The outside spring doesn't really do anything, right? It just keeps the smaller spring in the center.) I did notice that the springs I'm replacing don't really seem that different. I included some pictures below, new springs on the right and old spring on the left. The new ones are definitely a little taller. Not sure if that makes a difference.

The bigger thing I noticed is inside the back half of the valve. The threads for the velocity adjuster are kinda messed up. They're not stripped, not yet anyway, but the anodizing has been completely rubbed off. Is that normal?

I'm going to do Walker's "mag reset" thing tomorrow if I have time. Just sharing this for now.

[rawbutter]

Oh...one more thing I forgot. When I was putting in the barrel and tightening everything down, I noticed that the front of my Dye UL barrel could wiggle a little, even after I tried to tighten it down farther. I did some testing, and yeah....the two halves don't screw in straight. There's an offset about 1 mm from one end to the other, which is plenty enough for the paintball to bounce/roll off the inside of the tip as it comes out. No idea how long that's been like that, but I'm assuming it was bent last time I played when I was breaking multiple balls every single game, so maybe that's the culprit and I've been doing all this other worrying for nothing.

I've got other barrels I can use to test out everything this weekend. Hopefully everything works fine with a different tube and sucks when I put the Ultralite back on there. Then I know I just need to replace the barrel, which is easy enough.

[nak81783]

I would advise to test one variable at a time. The barrel sounds like the issue, so try a different barrel first, using all the original marker parts, not the new ones.

Briefly reviewed thread. Didn't see where you tried the suspect barrel on one of your other markers. Might want to try that too. If the problem follows the barrel, I think you've figured it out.

Let us know. Good luck.

[rawbutter]

Briefly reviewed thread. Didn't see where you tried the suspect barrel on one of your other markers. Might want to try that too. If the problem follows the barrel, I think you've figured it out.

Good point. I'll give that a try too.

[rawbutter]

I think I figured it out. I'm not 100% sure, but I'm pretty confident that it's my tank regulator.

Here's what happened today.

I started with the Dye Ultralite barrel. Unfortunately I've already unscrewed the two halves, aligned them better, and screwed them back in carefully, making sure everything was perfectly straight. So I couldn't check to see if the original misalignment was the culprit. But I took out my Gmek and a J&J ceramic barrel. I shot a pod through the Gmek and the J&J, no breaks. Then I switched barrels back to my Dye Ultralite and shot through another pod. No breaks again. So, at least the barrel is straight now. I don't think that was the main problem, but it's good to have piece of mind about that.

Next I put my Automag together with the original parts and did a reset. I did use a different tank (a basic First Strike 48/3000) and the J&J ceramic barrel. I started with the regulator low enough not to shoot and then got up to speed. When I started shooting paintballs, I used Valken Graffiti, which is pretty hard stuff. I was able to shoot a pod without breaks. Then I switched to the Dye Ultralite and was able to shoot through another pod without any breaks. Then I switched the paintballs to GI Sportz Xballs, which are considerably more brittle than the Graffiti, and shot through another pod. No breaks. That felt very good.

So, it's gotta be the tank, right?

I have a First Strike carbon fiber tank on an old MacDev LegionAir push-button regulator. (See attachment for an old picture.) If you're not familiar with that regulator, you're not alone. It's an old direct-mount reg that's super duper rare. MacDev doesn't sell parts for it anymore. They don't even have specs for it. I've literally had to reverse engineer the whole thing to order replacement o-rings and springs. But, it uses standard parts, and it uses Belleville washer spings instead of a regular spring, so I've never had much trouble rebuilding it. I just did it last summer, actually.

This is the whole reason why I was sure the tank regulator wasn't the problem in the first place. I just rebuilt it less than two years ago, and I checked the output pressure at the start of this whole fiasco. It was putting out 900 psi. But since I had eliminated everything else, I decided to check the output pressure again. And low and behold, it was still putting out 900 psi. Great.

This was very dumbfounding to me. I literally sat there with the tank in my hand, eyebrows furrowed, not believing the number. But then, after 30 seconds or so of stewing, I noticed that the needle on the gauge was moving up. It was slow, but it rose to 1000 psi within a minute or so. Then I watched it climb to 1100. I'm sure it would have gone even higher, but my testing gauge only goes up to 1200, so I degassed before it went that high. I've ruined gauges before maxing them out, so I didn't want to risk that happening again.

This totally could explain it, though. If my tank regulator has been creeping, that would affect velocity.

Which brings us full circle back to the "first shot hot" part of the title that I said earlier was a mistake. I said it was a mistake because, well, when I'm getting ready to start a game, I turn on my air and fire a test shot about 30 seconds before the game starts. I never break paint then, so I back-peddled on the "first shot hot" theory. But here's the thing. For that first test shot, the gun has only been pressurized for a few seconds when the tank reg is putting out 900 psi. After that, though, the game starts, I run out onto the woodsball field, find a tree....and then I wait. There are many, many times while playing that I don't shoot for a few minutes while I'm sneaking around or waiting to make a move, and during that time, the tank reg pressure output is going up and up. Then when I finally take a shot, it comes out hot and I break paint. I know that's really unusual, but it fits the facts. And changing the tank (and fixing the barrel) made the problem go away.

I'm going to order some new o-rings for the tank reg. They should be here in a few days, and I'll post another update then. But I'm hoping this will solve the problem.

Sorry this post is so long, but thanks for all the help and patience.

[superman]

I am not sure how that reg is setup but your likely going to need a reg seat if that is an oring in that style reg great. If not i would recommend picking up something that mags like better. like a powerhouse set to the pressure you prefer.

[rawbutter]

I am not sure how that reg is setup but your likely going to need a reg seat if that is an oring in that style reg great. If not i would recommend picking up something that mags like better. like a powerhouse set to the pressure you prefer.

This is the MacDev regulator piston. There's no reg seat seal thing on the tip of the stem (unless it fell out and I didn't notice). There are only two o-rings: a big one at the bottom and a smaller one towards the top. There is a little round indentation on the tip of the stem, but it's still aluminum. No seal material.

So, I should be able to rebuild this by just changing the o-rings, right?

[nak81783]

I have doubts.

If you're willing, try the suspect tank before fixing it to see if you break paint. Perhaps time how long it takes the reg to creep to 1100 psi or so, and then recreate that when hooked up to the Automag to see if it breaks paint.

The reason for my doubs - the X-Mag (with X-Valve) manual says not to exceed 1000 psi input, or it could damage the valve. However, I see one a a handful of scenarios happening. Go back to the diagram earlier in the thread for reference.
1. The X-Valve is a beast, and even though you're above 1000 psi, it still regulates it. Although I don't have personal experience with this, I believe many people have gone to 1200 psi on RT/X-Valves to get RT/trigger bounce. I understand you may have crept beyond 1200 psi given the patient play style you described above, but see 2-4 below.
2. The excess pressure gets by the aft reg pin assembly o-ring, and vents out the side of the valve. This vent hole isn't shown in the diagram earlier in the thread, but it's between the two #6 o-rings just forward of the belleville washers on the reg pin assembly.
3. The excess pressure gets by the reg seat o-ring and vents through the reg piston safety feature.
4. The excess pressure gets by the reg seat o-ring and vents through the top vent hole.

AGD really did their homework with safety features and vents to diagnose issues.

Going back to the barrel, did you see the offset forward looking aft (tip to breech) or aft looking forward (breech to tip)? Curious if there was a 1mm (~0.040") "dam" as the paintball went down the barrel or just an uneven opening into the barrel tip. The dam would wreak havoc on paintballs traveling near 300 fps down the barrel. An uneven transition into the barrel tip may cause issues but is far less likely, since the paintball already made it through a smaller bore barrel back, and the tip, even though unevenly offset, is still larger than the barrel back all around the circumference.

If you were able to fix the barrel, it sounds like it was cross threaded, so I'm not sure how to recreate this without risking cross threading the barrel again.

[rawbutter]

I have doubts.

If you're willing, try the suspect tank before fixing it to see if you break paint. Perhaps time how long it takes the reg to creep to 1100 psi or so, and then recreate that when hooked up to the Automag to see if it breaks paint.

The reason for my doubts.......The X-Valve is a beast, and even though you're above 1000 psi, it still regulates it.

You're totally right that the x-valve can handle insane amounts of pressure. We've all seen the video of the 3000 psi scuba tank hooked up directly to an RT valve with no regulation. The difference here is that the input pressure is changing. If I set up my x-valve to shoot at 280 fps with the tank at 900 psi output, but then later the same tank is putting out 1100 psi or more, it won't still shoot at 280 fps. It will shoot faster.

I am right about that, right?

I mean, I remember one time my friend's tank blew a burst disc for no reason, so he borrowed one of mine. But he had a Mini that was set up for a low pressure tank, 400 psi output IIRC, and when he screwed in my high pressure tank, it messed with his velocity.

Going back to the barrel, did you see the offset forward looking aft (tip to breech) or aft looking forward (breech to tip)?......

If you were able to fix the barrel, it sounds like it was cross threaded, so I'm not sure how to recreate this without risking cross threading the barrel again.

I couldn't see the offset looking down the barrel. I laid the barrel on two thin scrap pieces of wood, one under each end so it formed a bridge, and then measured the distance in the middle from the top of the table to the bottom of the barrel with a feeler gauge. Then I kept rotating the barrel and re-measuring. That's where I got the 1 mm offset.

And the barrel was not cross stripped. There's an o-ring inside the two halves that had worn out, and the fit wasn't quite perfect. The OD of the tip was a few thousandths smaller than the ID of the back. I replaced the o-ring and then wrapped the tip threads with some Teflon tape to fill in the gap. That worked really well. I can still measure a little bit of an offset, but it's like 0.05 mm. Close enough for me.

[Spider!]

Yeah, 1100 works in the valve. Make sure the hoses and connections are good for the pressure and the flow. 1100 would get me around 19 bps, and 900 would be around 12 bps. An adjustable reg could hit everything in between. That was with a gold spring; I can't remember how much difference a red spring made.

[LukeAO]

You're totally right that the x-valve can handle insane amounts of pressure. We've all seen the video of the 3000 psi scuba tank hooked up directly to an RT valve with no regulation. The difference here is that the input pressure is changing. If I set up my x-valve to shoot at 280 fps with the tank at 900 psi output, but then later the same tank is putting out 1100 psi or more, it won't still shoot at 280 fps. It will shoot faster.

I am right about that, right?

That assumption is incorrect, that's not how the X valve functions.

[rawbutter]

That's not how the X valve functions.

Well, then I'm stumped. But at least I've identified a few things to fix. And it's shooting well now. So I'm happy.

[Spider!]

That assumption is incorrect, that's not how the X valve functions.

Are you referring to shoot-up/down during RT from input pressure? Tom's explanation used to confuse me.

I get higher input pressure leads to higher temperature in the valve, which I've seen. But it seemed like he said the velocity would drop some from higher input pressure during RT.

I've only noticed it in one setup where I got a increase in velocity during RT. I think it was a classic RT. I don't remember the pressure, but the timeline makes me say it should have been 900.

Tom's velocity charts have disappeared a few times from AO. I haven't looked lately.

[LukeAO]

My statement is in reference to the function of the valve, not the nuances of how heat effects the system over all. You can split hairs if you like but the the X valve regulator is what it is.