My Pneumag and Lvl 10 middle spring woes!

[longi]

Does anyone have the same problem as me and manage to cure it? I only seem to be able to walk my Pneumag using the short spring. If i try to use the middle spring, i can't make it walk. If i use a standard unmolested intelliframe with the middle spring, i can bounce the trigger to and attain high rates of fire. I though i'd sorted once already by giving the valve a good clean, but no. I use a Centerflag hyperflow 4500 psi reg (850 psi output) on a 68/4500 bottle. I'm pretty certain it's some to do with the LPR, but i can't seem to pin point the problem. So far i've tried more rod length, moving the MSV-2 around, adjusting the LPR +/- pressure, messed about with LVL10 shims, carriers and oil. I've also checked the hoses for kinks. I'm open to suggestions as this is really driving me mad!
Heeeelp!!!

[rawbutter]

If you change out the shorter spring for a longer one, you'll have to slightly increase the velocity until the Level 10 bolt fires consistently. You shouldn't have to change the LPR, though. Well, maybe you'll need to up it ever so slightly, but not too much.

When you say that you "can't walk the trigger with a longer spring," what exactly do you mean? Does the gun still fire, and the trigger is just too heavy to walk, or does it not even fire anymore.

[Mechanic79]

Make sure you rechrono the gun when you make changes.

I've also noticed that adjusting the trigger stops had made a large difference in my set up; the shorter the better.

[longi]

I've increased the velocity back up to 280 fps. The gun still fires fast single shot. The trigger is very light. When i say i can't walk the trigger, i mean the triger is plenty light enough, however, when the gun fires it chuffs and kind of short strokes. I'm able to attain high rates of fire walking the trigger if i use the short spring, but not the middle spring. It just fires almost as if it's on the edge of firing very fast, but not quite making it. If i start setting up the LPR from scratch and gently turn up the LPR pressure until it fires quick single shots it works fine, but not if i try to walk the trigger. It's almost like it's being starved of air. I used right angled hose fittings where i could so there would be no kinks or pinches.

[longi]

I used a chrono to set the velocity when i got home from work. I've also adjusted the trigger stops around too. I also lengthend the trigger rod in case i wasn't getting enough air the the MSV-2.

[Mechanic79]

If i start setting up the LPR from scratch and gently turn up the LPR pressure until it fires quick single shots it works fine, but not if i try to walk the trigger. It's almost like it's being starved of air. I used right angled hose fittings where i could so there would be no kinks or pinches.

Adjust your trigger stops so the MSV-2 gets minimal travel. for lack of better term, just mess around with the trigger stops. or try the Magnet Mod from Cyberave68 to get a faster response.

I've yet to install the magnet mod on my pneumag but I did notice while tuning that adjusting the trigger stops short as possible made the most difference. I'm using level X and ULT.

[longi]

The ULT didn't work out too well for me, i was pretty dissapointed with it's performance. I'll try the shortening the trigger stops, but i'm pretty sure it's not that. I found that if i had more slop in the trigger it was alot easier to walk the trigger. The MSV-2 already has minimal travel on it, although i am now showing the trigger more rod now. The upshot of that was it's made the rate of fire higher with the short spring which was already high!

[rawbutter]

If i start setting up the LPR from scratch and gently turn up the LPR pressure until it fires quick single shots it works fine, but not if i try to walk the trigger. It's almost like it's being starved of air.

I remember getting similar results when I built my pneumag. I would turn up the velocity a tad more, but what Mechanic79 was saying about trigger stops is dead on. If you have too much slop in your trigger, then you might be actuating the MSV-2 before it's fully expelled the air from your last shot. Basically, you're firing a second shot before the spring has a chance to return the bolt.

So mess with the trigger stops. Make it so that the trigger stops a moment after the gun fires. If you hold in the trigger at that point, the "leaking" sound from the msv-2 will be almost at it's loudest point, but it will work the best. And if you're shooting quick shots, the air loss will still be minimal.

[longi]

ok i'll give it a go after work. :)

[Hilltop Customs]

Basically whats happening is the same as short stroking....the MSV-2 is "riding the trigger" keeping pressure on the sear and keeping the on/off from fully resetting. This small amount of pressure difference is only noticeable with the longer springs beacuase of the balance between the pressure pusshing the bolt forward and the spring. longer springs mean its closer to being balanced, and the small pressure difference will unbalance the system and the bolt wont have enough pressure to fully cycle.

make sure you have the hose between the MSV-2 and the ram as short as possible and no real tight bends in it. It could also help to put the spring back in the mpa3 if you dont have it. If you havent done it already, lube your on/off assembly. Using the minimum pressure(LPR) required to cycle the gun will also help because it will reduce the amt of air needing to flow through the 3way and hoses. A spring or magnet return for your MSV-2 would also help to return it to exhaust faster.

[Mongoose]

I remember getting similar results when I built my pneumag. I would turn up the velocity a tad more, but what Mechanic79 was saying about trigger stops is dead on. If you have too much slop in your trigger, then you might be actuating the MSV-2 before it's fully expelled the air from your last shot. Basically, you're firing a second shot before the spring has a chance to return the bolt.

So mess with the trigger stops. Make it so that the trigger stops a moment after the gun fires. If you hold in the trigger at that point, the "leaking" sound from the msv-2 will be almost at it's loudest point, but it will work the best. And if you're shooting quick shots, the air loss will still be minimal.

I agree with everything said above..also can you post a pic of your internals...
depending on your 3-way setup...you might be able to use the magnet mod...which has worked wonders with this problem!

[longi]

Here's my internals.

http://www.putfile.com/pic/7565147

[longi]

I've cut down the hose between the QEV and the MPA-3 down to about 2 inches long, and i've straightened up the MSV-2 so as to make it straight with the intellimount. Unfortunately i'm almost out of air in my dive bottle. I adjusted the stops but it made no difference. The trigger pull was only around 2mm anyway and any shorter than 1.5mm. and it wouldn't fire consistantly. How are your 3 ways mounted? Are they mounted at a slight angle to the intellimount or do they run parallel with it? I know i spent quite a while faffing around with it to get it fire consistantly, so it could also be this.

[rawbutter]

I don't think the angle of the msv-2 matters, but if you want to compare, you can see pics of a lot of different pneumags (and the internals) in this thread: http://www.automags.org/forums/showthread.php?t=222337

Your low air tank could be the culprit too. Mags don't like to fire once you start getting close to 1000psi, so if your tank is low, that could also be causing problems.

I did the same thing, by the way. I got everything set up, started testing with an almost empty tank, and got really confused about why it wasn't working. As soon as I refilled, though, presto!

[longi]

My tank's down to around 1400 psi now so it does need filling. When it is full it fires ok down to about 2000 psi but not below. I had it bouncing using the middle spring last week all the way down to around 1000psi. I made the classic mistake of changing the o rings, which actually helped it feel like a much tighter package, then i stripped the valve down and cleaned it with warm soapy water and i couldn't get to run as well as it had prior th cleaning it. (The Pneumag that is). I've still got alot of testing to do once i get my dive bottle filled. I'm determind to sort it out.