Air Venturi Avenge-X regulator creeps downward

[superduty250]

I have a .25 cal avenge-x tactical bottle version and have been shooting a lot of full strings while tuning. I have noticed a gradual regulator pressure drop as the bottle pressure drops starting around 3000 psi or so. Searching these forums, I found that AEAC Steve says this is normal for the rifle. Are there any mods or tweaks to improve the regulator to keep the regulator pressure more constant at its set point? I know there are aftermarket regulators for more high-end brands like the FX but I have not seen anything for the Avenge-X.

I just started working a tune using Steve's process for 910 fps for the JSB 25 grain pellets. So far for my first attempt I was able to get an ES of 16 and a SD of 3.5 over the first 100 shots so I suppose it's not that bad. I just purchased the rifle last month and have gone through about 1800 of the 34 grain pellets and 600 of the 25 grain so far. Should this be enough to get it broken in completely?

 

[nervoustrig]

Regarding the regulated pressure changing with the reservoir pressure, the term is input regulation rather than creep but they do share a common cause.

Drop in Reg Pressure over a string of shots

I’m bugging you guys once again from Patagonia, Argentina with a couple more issues on my Impact MK2. I am getting a drop in reg pressure of about 10-13 Bar over a 50 shot string. I have a MK2 .25 with Power Block and 72 Power Plenum Upgrade, slug kit. Shooting 34 grain slugs at 945fps...

www.airgunnation.com

I just purchased the rifle last month and have gone through about 1800 of the 34 grain pellets and 600 of the 25 grain so far. Should this be enough to get it broken in completely?

Yes, that is more than sufficient to be broken in.

 

[superduty250]

Regarding the regulated pressure changing with the reservoir pressure, the term is input regulation rather than creep but they do share a common cause.

Drop in Reg Pressure over a string of shots

I’m bugging you guys once again from Patagonia, Argentina with a couple more issues on my Impact MK2. I am getting a drop in reg pressure of about 10-13 Bar over a 50 shot string. I have a MK2 .25 with Power Block and 72 Power Plenum Upgrade, slug kit. Shooting 34 grain slugs at 945fps...

www.airgunnation.com

Yes, that is more than sufficient to be broken in.

Thanks nervoustrig for the link, lots of info there! I should have been able to find it myself, but apparently I didn't hit upon the best search terms.

For now, I'm just not going to worry much about it until I check out the accuracy of my tune. So far I've just been checking fsp spread and std. My regulator input pressure is dropping from 150 down to 130 bar over 100 shots but does not seem to impact the fsp all that much until the bottle supply pressure gets below the regulator set point. It's too cold in Virginia right now to get out of my garage!

 

[superduty250]

More Avenge-X regulator questions:

nervoustrig, in your post regarding making insert out of harder delrin, how did you cut out the new inserts out of .04 plate? I was looking at maybe using delrin round stock and parting them off. Back 50 years ago I worked as an N/C machinist for the shipyard here in VA. We made delrin valve seats for high pressure steam valves and the material was a redish-grey as I recall. Can you get the old one out by punching through the hole on the other (larger) end? I am probably going to polish the original first. Under magnification, I can see a faint imprint from the mating part down in the aluminum body. Looks like a .125 or so hollow pin down in there but I have no idea how to get to that part or if it even is meant to come out, so don't know if I can polish that also. Can't identify that part on the schematic from Pyramyd Air's website.

Also, I purchased a backup regulator just in case I screw one up. I disassembled it to have a look at things and noticed that it has a different Belleville stack than my stock one which is in a .25 cal Avenge-X. The original stack is arranged
))(())(())(())(())((. The replacement stack is ))(())(())(((()(. Mistake or for different spring rate? They do both have the same .023 thickness and .039 height. Stock one has 0.528 total length, the replacement 0.496.

The original was lubed faily heavily with a thin oil on o-rings and in the washer area The new one's washer stack was completely without lube. I see people who are polishing the regulators various parts and areas. From what I see, other than the seat insert, the part that could affect things the most would be how easily the o-rings can slide within their bores. Mine does not slide smoothly at all even with the thin oil. I am thinking polish the bore and lube with silicone grease so it slides smoothly to see if that help my shot to shot constancy. However, the brass shaft with the O-rings may not even see enough travel during operation for lubing to have any impact.