Avenger Slow Regulator

[toddbrat]

Just replaced the regulator on my .22 Avenger, the old one was extremely slow and creepy. I noticed the donut dent in the Delrin after I removed it so I probably over-tightened it at some point.

The new reg is installed and, while not creeping (yet) it is still extremely slow, to the tune of taking up to 30 seconds between shots to  come back up to pressure. I've currently got it set to 1400psi with 2 1/4 turns in on the hammer spring (AEAC's economy tune), I haven't tried it any higher as I'm still breaking it in. Curious if anyone else has seen them this slow. It is pretty much on-par with the time it was taking the old one as well.

I should also mention it doesn't matter what my fill pressure is, this same thing happens from 4k psi all the way down to 2k. It could be it isn't broken in yet, but it seems odd that two would be doing the same thing.

[avator]

I hope you get this sorted and report what the issue was. I don't have the issue but I'm curious as to what could cause this.

[nervoustrigger]

As you said, the slow recovery could just be an artifact of the break-in period.  Until the plastic seal at the end of the piston has become ironed in to the conical seat, it will take a while to settle out to the final pressure.  However if it persists, here are a few potential causes to consider.

One is that a piece of debris is partially blocking the tiny orifice feeding to the conical seat.  I don't know the size of the orifice in the Avenger reg but they're usually very small.  Smaller than a common sewing needle...might need to look for a scrap piece of small gauge stranded copper wire and harvest a strand from it and try pushing it through the orifice to clear it.  Soft copper is advantageous here because you absolutely don't want to scratch the seat, which brings us to the next thing to check...

Inspect the apex of the cone carefully with the aid of magnification.  It should be perfectly flat and smooth.  If it has a scratch or machining marks, it will be prone to slowly weeping air past the seal until the pressure rises enough to fully squish the seal closed against it.

And then this last one is of a similar nature to the clogged orifice.  I don't recall if the Avenger has one but some regulators have a restrictor screw.  For example, on a Huma regulator it is a small (M3) grub screw inserted into the brass adjuster:



It relies on air passing through the slight gaps in the threads.  If it has a bit of debris or threadlocker blocking it, the regulator may recover very slowly.

Good luck.  I'll keep an eye on the thread.

[PasadenaMike]

Have you contacted air Venturi?

[3crows]

And then this last one is of a similar nature to the clogged orifice.  I don't recall if the Avenger has one but some regulators have a restrictor screw.  For example, on a Huma regulator it is a small (M3) grub screw inserted into the brass adjuster:



It relies on air passing through the slight gaps in the threads.  If it has a bit of debris or threadlocker blocking it, the regulator may recover very slowly.

Good luck.  I'll keep an eye on the thread.

I have two Houma regs and each has a flat driver head screw, not a grub screw. It was mentioned in the instructions that a flat could be filed into the screw threads to hasten air flow, which I did. I wrap a piece of lock wire around the screw so I can retrieve the regulator for adjustment or maintenance without disassembly of the rifle. I guess the question is does the Avenger regulator have a flow restrictor like the Houma types?

Look to the far right, the screw sticking out is a flow restrictor and of course, as I said, can be used to wrap a wire loop for removal:



One other thing, I bet there is a tiny orifice in either the gauge or the port into which the gauge installs that has the purpose of restricting air flow should a failure occur. Thus the gauge itself may be lagging well behind the actual pressure in the plenum and as the delta decreases between plenum pressure and the pressure in the gauge Bourdon tube that orifice, in between, will make the final little bit very slow.

[toddbrat]

Thanks all, the reg on the Avenger is built a bit differently. Here's a pic and you can also see the "donut" in the delrin where it was over-tightened. I bumped up the reg pressure to about 1800 and I'll run a tin of pellets thru it and see if that'll help set it. While I'm a fan of the platform overall, and when it is on, it is really on, but even though I generally use the single-shot tray, waiting 30-45 seconds between shots does get to be an issue when I get limited trigger time these days as it is.

[nervoustrigger]

For what it’s worth, the impression in the plastic seal may be from inadvertently driving it against the seat but it’s also what you’ll see from normal use.