AV Avenger - POI changes after air fills

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S

SMFB

Member
Oct 19, 2022
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Lakewood, California
Hi everyone,

I recently picked up an AV Avenger for my first PCP rifle. I have it paired up with a Sightmark Wraith for the optic and also have a DonnyFL suppressor along with the barrel adapter. The thing is a tack driver and I can consistently hit the same pellet hole on target with rifle.

The problem happens when I fill the gun. I fill up to about 3900-4000 psi, I have the regulator set to 2600. After dry firing about 5 times to settle things in, the shots are usually off zero from about an inch. It doesn't always happen, but its definitely air fill related and happens after. I'm assuming its barrel band related right now so I went ahead and ordered the Black Arts barrel band kit. Anyone have some thoughts on this issue? It drives me crazy after having a perfect zero and then having to redo it.

The pellets I have my initial zero with are the JSB Jumbo Heavy's.
Ammo used:
18.13gr JSB Jumbo Heavys @936 fps
18.52 H&N Barracuda Hunter Extreme @916 fps
20.2 Nielsen slugs @847 fps
 
WorriedMan said:
SM,
There was a recent thread about this, search the archives, might even have been an Avenger. Think someone suggested a slight swelling of the air tube as a possible cause, can't recall the other suggestions. Best of Luck, WM
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Yeah I just saw that now actually. They seem to say that don't fill it to the max fill pressure and back off instead to something lower. They also put on a new after market barrel band, but theres been no follow ups since.

I'll try the fill pressure advice, but things like that just trigger the inner OCD demon in me. Like why cant I fill it to the factory setting/why doesn't it just work as intended?
 
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With PCP's the tendency to shift poi when the gun is filled to its MAX pressure is a well known phenomenon. That's why it's best to figure out what each individual gun's "sweet spot" (optimal accuracy & at what range of pressure) is going to be. Why bother filling it to max pressure only to be throwing away the first few shots. It's not uncommon.
 
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Wackamole said:
When you fill a bottle or cylinder they expand witch than puts tension on the barrel band. Why it doesn’t happen to all guns is a mystery
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The barrel band on an Avenger has about 1mm clearance to the shroud all the way around unless you adjust the grub screws on each side to push the shroud against the top of the band.
 
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AirArcher66 said:
Any gun that has any POI changes for any reason would be sent back immediately and definitely would go for a different brand/model.
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I kinda like my Avenger shooting NSA 17.5gn slugs in .385" outside to outside groups center to center at 51 yards. Does have the new Troy Hammer barrel though.
1666289730308.png

Don't feel left out!

My very first 5 shot group from Troy Hammer's new barrel design. .22 Avenger with a 24 inch barrel. 51 yards shooting .2165 NSA17.5 @950fps. That's a 1inch target dot. Using a Swede high capacity mag. Shooting off an Atlas bipod and rear bag as I'm eaten alive by mosquitoes. I think he has a winner.
www.airgunnation.com www.airgunnation.com
 
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heavy-impact said:
I kinda like my Avenger shooting NSA 17.5gn slugs in .385" outside to outside groups center to center at 51 yards. Does have the new Troy Hammer barrel though.
View attachment 298924

Don't feel left out!

My very first 5 shot group from Troy Hammer's new barrel design. .22 Avenger with a 24 inch barrel. 51 yards shooting .2165 NSA17.5 @950fps. That's a 1inch target dot. Using a Swede high capacity mag. Shooting off an Atlas bipod and rear bag as I'm eaten alive by mosquitoes. I think he has a winner.
www.airgunnation.com www.airgunnation.com
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If it does not have POI shifts it's great,
if it has POI shifts I don't care how small groups you can print, for me as a hunter it's useless,...even if I can print dimes at 100 yards ;)
 
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AirArcher66 said:
If it does not have POI shifts it's great,
if it has POI shifts I don't care how small groups you can print, for me as a hunter it's useless,...even if I can print dimes at 100 yards ;)
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So if it moved a third of a squirrel head that wouldn't work?
I haven't experienced any poi shift but I wouldn't fall to the floor kicking and screaming if the first shot was a half inch off the others.
O - Copy.jpg
 
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heavy-impact said:
So if it moved a third of a squirrel head that wouldn't work?
I haven't experienced any poi shift but I wouldn't fall to the floor kicking and screaming if the first shot was a half inch off the others.
View attachment 299134
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I would, I find it unacceptable for a hunting gun to have any kind of POI shift, might be 1/2' today and 2.5" tomorrow....I would never, ever have confidence to take a gun hunting that I know has possible POI shifts, No way !

Those 2 groups mean nothing,....POI shift is when you put a gun away that printed great groups right at your zero, but when you take her out the next day it will still print great groups but not at the same place it was the day before.
 
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AirArcher66 said:
I would, I find it unacceptable for a hunting gun to have any kind of POI shift, might be 1/2' today and 2.5" tomorrow....I would never, ever have confidence to take a gun hunting that I know has possible POI shifts, No way !

Those 2 groups mean nothing,....POI shift is when you put a gun away that printed great groups right at your zero, but when you take her out the next day it will still print great groups but not at the same place it was the day before.
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I don't think I've ever encountered that. I have seen guns throw the first shot off due to regulator creep or maybe a gun with a noodle for a barrel like the impacts. If you prop them against the shroud or lay them on something that contacts the shroud it can move the point of impact until the noodle relaxes again. I've never seen an airgun have a random point of impact from day to day.
 
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heavy-impact said:
I don't think I've ever encountered that. I have seen guns throw the first shot off due to regulator creep or maybe a gun with a noodle for a barrel like the impacts. If you prop them against the shroud or lay them on something that contacts the shroud it can move the point of impact until the noodle relaxes again. I've never seen an airgun have a random point of impact from day to day.
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On the contrary,...I never had one but I sure read and heard many accounts of guns doing just that.
 
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So an update.
I received the black arts barrel band and started stripping everything down. I noticed a few loose things on the gun itself when doing so, namely the barrel itself. I guess I have a newer gen avenger because instead of a set screw for the shroud being held on, it was threaded. The videos i've seen for tear downs were different for what I had to do. In either case, it wasn't seated properly.

I installed the band kit, filled it up only to 3800psi and began the re-zero process for the 3 pellet types I use (the scope stores profiles/zeros). Threw the gun on a lead sled and everything is lights out dead center after zero. Multiple fills and its still holding.

So was it the barrel band or high fill pressure? Both? Who knows!?

To be honest I do love the gun because you get a lot of bag for the buck. Knowing what I know now though I probably woulda just went with a dreamline. I expect things to work as intended and not have to do after market tweaks and or sacrifices to old unanamed gods in order to make things work.
 
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