Hello, the barrel band is f*cking part of the avenge-x tactical. Here is my story:
I bought avenge-x tactical bottle version with aluminium bottle (rated to 250bar, 17J energy limit in my country) .22 for my 15y son.
We used bipod and no back support (no sand bag, just free hand) on 15m distance. We were not able do get better than 5mm ctc. It was very variable 5-10mm ctc at 15m distance. We tried many pellet brands, cleaning barrel, checked our hands if not poopty... nothing helped. Than I was looking on the gun in our living room and I found it: The bootom side picatinny rail part is very bendable. the Barrel band mounted on it was pulling the barrel down (connection to the shroud is tight, contact with the bottle is loose) and every time it was moved on the bipod it was pushed up and to the sides. So I decided to remove the barrel band. The weapon's zeroing has changed drastically. I made a new scope zeroing at 30m distance when no wind outside. so the barrel was bent before. The accuracy is now impressive.
I have got ctc 2-3mm at 30m with no support on the back of gun, just bipod and my hand on grip. I am average shooter so the ctc with fixed gun at 30m will be unmeasurable. Muzzle speed is just 175m/s - 17J legal limit in my country (limited by transferport), I use JSB exact jumbo 1.03g 5.50mm