Sniper's velocity lowers during the day- it's gotta be in input regulator...right?

[The Inflicted]

Maybe, but I’m leaning towards not necessarily. I was thinking of light hammer strikes or valve hole not lined up with bolt hole. The problem being intermittent is perplexing.

I wouldn't describe it as "intermittent". Once the velocity halves, it stays that way consistently, at least for the rest of the day, as I've observed.

Maybe try putting the 32 Degrees ASA and Wrath HPR back on under pressure. Let it sit for a while, maybe in the sun to warm it up, as you mentioned, and see what each gauge reads. I’m curious if both pressures go down, meaning that ASA is starving the marker either from the ASA pin going to far or not far enough towards the tank.

The experiment is worth a shot. I've also got some inline gauge adapters around here somewhere that I could use to monitor the Azodin reg's output, and hopefully enough sunny days left that I can let the gun heat up on the porch while I get some work done.

[The Inflicted]

What about paint swelling? did you check the paint fit later in the day?

Wouldn't think so, since I'm not having the same problem with other pumps, even other Snipers, even when I'm using the same paint from the same hopper in them on the same day as the malfunctioning gun.

Besides, my experience with swelling paint is that it tends to raise the muzzle velocity slightly, not abruptly cut it in half.

[The Inflicted]

If it were just a leaking reg seat, wouldn't you be back to normal velocity after degassing and regassing at the tank?

That's a good thought. If I can get the problem to happen again, degassing the gun and regassing to reset the reg piston is the first thing I'll try.

[The Inflicted]

It was pretty warm and very sunny day today so I was able to run some tests and...

It's not the regulator... but it is temperature-related.

I kept the Azodin reg on the gun but put a LAPCO dual tank adapter between it and the gun and screwed a gauge into it. The gun was set to operate at around 430psi, which is kind of high but it is a minicocker, and I've got a thing against that pumps that make a farty sound.

Anyway, I chronoed the gun at 290fps and then left the gun (with no paint) in hot sunlight for an hour or so. Coming back to the gun it was so hot that the grip was uncomfortable to hold. However, the Azodin reg was holding steady at 430 and the gauge on the ASA showed that the tank was still putting out around 800psi.






Chronoing the gun with paint (the same paint I used the last time I had the problem) showed that the velocity had dropped by more than half- about 130fps when the shots would even register.
Degassing and re-gassing the gun did nothing to change the problem.

I degassed the gun, brought it inside, and set it on top of an air conditioning vent to cool. After an hour or so I re-gassed and re-loaded it and once again it was shooting at 290fps. Paint out, gas on, another 30 minutes in the hot sun, and again, velocity was down below 150.

To see if it was the temperature and not just sitting gassed up that was causing the problem I let it cool down again and tested the velocity (again, 295 or so) and left it gassed up inside the garage where it's cool.
After an hour, no change, so it's my assumption that getting hot is somehow causing it to shoot way under, though at this point the mechanism making that happen does not appear to be regulator-related.

[Myrkul]

The only remaining thing that would make sense to me is the cup seal. Could the heat be making the cup seal get too soft and sticky?

[latches109]

Sounds like the reg piston oring is swelling and sticking.

did you change this?

[russc]

Probably a thermal expansion issue. Id guess either between your valve stem and valve body, or your hammer and the body. First guess would be hammer and body...but that's kind of weird because the aluminum body should be expanding faster than the steel hammer, and most valve materials will expand faster than the steel stem.

Quick check would be to heat your gun up in a degassed state and with the trigger depressed, move the cocking knob and hammer back and forth in the lower tube, depressing the valve, while feeling for any binding.

[nak81783]

did you change this?

I guess the question is, did it return, near-instantaneously, to 430psi after each shot when it was hot and shooting 130fps or less?

If yes, it’s not the HPR, right?

[The Inflicted]

I guess the question is, did it return, near-instantaneously, to 430psi after each shot when it was hot and shooting 130fps or less?

If yes, it’s not the HPR, right?

It did, yes. Pressure downstream of the HPR didn't budge before or after the heat.
Gauge is good, too- I had to adjust the reg prior to testing since I had taken it apart to inspect the seat and it was accurately showing the inline reg's output.

I'm ruling out the inline reg as the cause at this point, which is on the one hand is confusing because I struggle to think of how heat could be doing this, but on the other hand it didn't make a whole lot of sense for the gun to be demonstrating the same exact problem with two different regs which had been working properly on other guns.

[Cdn_Cuda]

What type of valve are you running in this? Could
it have internal orings in the valve?

[Myrkul]

I would absolutely check the cupseal at this point. I agree that it doesn't look like the reg, and I'm thinking the cupseal is the next softest part. I know the new phantom EV cup seals that everyone had issues with was too soft and causing the valve to stick, I wonder if something similar is going on here, where the heat makes the cup seal juusssst soft enough to stick. What valve is in this?

It's worth checking out at least. I think it's highly unlikely that ambient temperatures would impact either steel or aluminum this drastically.

[The Inflicted]

I'm not an expect at identifying cocker internals but aren't these stock WGP parts?

[Cdn_Cuda]

Yes look stock. So no internal o-rings.

[tyronejk]

I'm no expert at ID'ing cocker parts either, but is that cupseal made of delrin or other plastic? The theory that the cupseal is getting sticky in the heat seems to make sense to me too.

[Cdn_Cuda]

Heat that cup seal while it’s out of the body and see if it gets sticky. Also look for a fine crack maybe?

[Socalpumpballer]

I 2nd this theory. Those stock wgp injected molded plastic cup seals are hitting their expiration date. I’ve had all of mine go bad in the last 2 years on 4 different snipers

[Myrkul]

I've for sure seen at least one WGP cupseal go bad in the last year or so.

I like the idea of hitting this with a hair dryer to see what happens.

[coyote]

I had a similar problem with a sniper @ 20 years ago.

The IVG was backing out. Fixed it with a little plumbers tape.

Prior to that, just like you, I ran through a rogues gallery of inline regulators.

[nak81783]

Quick check would be to heat your gun up in a degassed state and with the trigger depressed, move the cocking knob and hammer back and forth in the lower tube, depressing the valve, while feeling for any binding.

Wanted to point you back to this as a good test. It replicates most/all the interactions rather than just heating up one piece.

[The Inflicted]

I had a similar problem with a sniper @ 20 years ago.

The IVG was backing out. Fixed it with a little plumbers tape.

Prior to that, just like you, I ran through a rogues gallery of inline regulators.

I don't think my IVG is moving.
Again, what I've seen 3 times this week in testing is that the gun shoots at full velocity when it's cold, allowing it to get hot in the sun will halve the velocity (290 to 130fps), and then allowing it to cool back down will restore the velocity to where it was previously.

I'm no expert at ID'ing cocker parts either, but is that cupseal made of delrin or other plastic? The theory that the cupseal is getting sticky in the heat seems to make sense to me too.

That made sense to me too, but doesn't seem to be the case. I heated the cupseal with a hair dryer until the stem was too hot to handle, but it wasn't sticking to the face of the valve.
Left the whole thing out in the sun for a bit, again to heat up, and same situation- not sticky.



I'm wondering now if somehow I'm assembling the valve and its jam nut and locking screw incorrectly to where the stem of the cupseal is binding in the valve, but I would think that the valve being pushed out of alignment enough for this to happen would cause leaks. Other than the metal moving a bit I don't know how if this is indeed what is happening it would be temperature-dependent.