Air venturi Avenger setting

[tny]

Hello everyone, 

I would like to gather information about the settings of the Air venturi Avenger .22

In some reviews they say they can do 60 consistent shots in full power and over 100 in low power.

Mine in .22 I'm running around 30-35 only coherent shots reg shots at reg 2100 psi and 60 shots at 1400 psi.

I wonder if this is normal... ?

My hammer spring doesn't affecting the speed ..

[mrbulk]

Hi Anthony,

I learned a lot about tuning my Avenger .22 by watching this one video (it starts about 33 or 34 minutes in):

[JimD]

I've only tried one regulator setting so far on my 25 caliber Avenger.  It is set at about 1500 psi, may be 1600, kind of hard to read.  The hammer spring is not turned in at all.  I tried a shot or two with the hammer spring screw turned in a little but velocity decreased so I turned it back out.  I will retry that when I turn the regulator up.  I was getting ~850 ft/second on the initial H&N FTT pellets so I saw no need to increase it.  But it shoots the slightly heavier FX and JSB pellets much more accurately and they don't quite go 800 ft/sec.  So I will turn it up a little. 

So I am tuned to fairly low power (although energy is about 35 ft lbs with the 25 grain, almost 40 with JSB Heavies).  I have never filled much past 4,000 psi but I am sure I cannot get close to 100 shots at my current tune.  I may not be getting 50 but I think it is around that.  I know I can get 35 or so with a fill to 3500 psi. 

I am interested with our comment on the hammer spring.  It seems like the current Avengers (mine is about a month old) have stronger hammer springs than the ones used in earlier models from the reviews.  I am thinking when I get to around 2100 psi I will need to turn the hammer spring in a little.  But your experience suggests maybe not.  I would say that means the spring is stronger than it needs to be.  In that situation, our only "tuning" is to change the regulator. 

My only other PCP is an unregulated Marauder pistol.  It definitely responds to hammer spring changes.  Although with the original transfer port only to a point.  I increased the size and can now usefully use almost the full range of hammer spring settings - but it goes through the air quickly at the highest hammer spring setting.  I backed it off a couple turns for the current tune and am pleased with it. 

I also noted in the manual that they say we may need to increase the hammer spring tension after awhile because it relaxes a little.  So after a few hundred shots I will check velocity again and if it is down, try again turning the hammer spring screw in a little.

[tny]

Hello JimD,

my avenger does exactly like yours, I also deduced that the hammer is too strong.

Set at 2500 psi the hammer influences a little bit depending on the setting but it remains too hard.

Did you do a complete series of chrony shots? I noticed that the shots lose power one after the other, look:

Reg at 1600 psi: only 32 shot:

Shot count: 32
Low: 278
Hi: 289
Avg: 285
Spread: 11
STD Dev: 2.2
 
288
289
286
287
288
286
286
287
287
286
286
286
286
286
285
286
285
285
286
284
284
284
286
283
284
284
283
283
283
284
278
too Down

Normally a regulated weapon does not have a downward curve, but a flat one it seems to me.

I would like to know how yours does 




Mr bubilk, i have see this video, but the shot count that he can do, it's impossible with the mine :-(

Cependant the barrel is good

[JimD]

I have not done a shot string with my Avenger.  I shoot about 5 shots when I change a setting or pellet to get the velocity.  I trust that the velocity will be pretty consistent until the tank pressure gets down to the regulator setting. 

While I agree there is a small downward trend in your shot string it isn't anything like the shot strings of my unregulated Prod.  For most of my strings, if I start at the full 3000 psi the gun is rated to handle my velocity will go up until I get down to around 2500 psi.  With the original tune, for instance, at 3000 psi I got 168 meters per second or 551 fps.  I peaked at around 2000 psi at 195 mps or 640 fps.  After seeing this, I decided to only fill it to 2500 psi to keep velocity around 600 fps which it will have down to about 1600 psi.  About 30 shots.  But velocity varies 50 fps over this string of 30 shots.  The tune I use now works best from 2700 psi where I am at little over 700 fps and doesn't fall under 700 for about 20 shots.  It gets as high as 751 fps.  I had another tune that varied less but was lower power.  I prefer this one since it shoots flatter and hits squirrels harder. 

I see the u tubes where they shoot long shot strings with regulated rifles but to me it mainly tells you how good the regulator is and how many shots you can get before refilling.  With unregulated rifles, I think it also tells you what sort of pressure to start at and getting the tune right is important to minimizing velocity variation.  But an unregulated rifle will always have more velocity variation than a decently regulated one.  The data I've seen, including yours, says the Avenger regulator is at least decent.  I would not expect to see much vertical stringing, for instance, at those sort of variations.  But I haven't shot past about 25 meters yet to see for sure. 

[JimD]

Anthony,

I could have mentioned this in my last post but I think your velocity is probably higher than you really want at the 1600 psi regulator setting.  On my 25 caliber the highest velocity I got at about that regulator setting was 263 MPS or about 860 fps.  It was with H&N Field, Target, Trophy which it doesn't shoot very accurately.  But the comments I see indicate that you don't want to push pellets much past 850 fps because they become less accurate, particularly at longer range.  I found out that the heavier 25-35 grain pellets my 25 Avenger likes are going less than 800 fps, about 242 mps for the Kings and about 220 mps for the King Heavies. 

Especially since you mention shot count, I would try 1400 or even 1200 psi regulator setting (but degass before going down on the regulator).  I would aim for around 260 mps for a combination of long shot string, flat shooting, and best accuracy with pellets.  My little Prod cannot get to 800 fps with the 14.3 grain pellets I use but it still shoots pretty flat.  The tune I use with it shoots 700-750 fps (220-230 mps) and is accurate and puts squirrels down quickly.  Dropping velocity should really help your shot count.

Jim