For what it,s worth. I tried moving the band forward,, I also tried 2 bands,,,, twice. Both times I got vertical stringing.(Up & down POI over a 25 shot string) Talking with a Friend that knows WAY more than I do,, we figure the air tube must "move" some due to varying preasures. I confirmed this by checking the spacing between the stock muzzle break & tube after 25 shots. It MOVED!! The gap changed!! Cant remember wich way,,, but I think it was accually touching the tube towards the end of 25 or 30 shots. Also,, I noticed when I removed band from the factory position (Off the gun),, the gap was HUGE,,, brl. pointing towards the sky!! Putting it on the front of the gun efectively "Bannanaed" that poor lil brl!! (shot like a springer) :p I noticed the steel breach did not fit down "snug" to the main tube,, unlike the fit on all my XX guns. I disassembled the gun & tried EVERYTHING,, 3 times!! :0 At my witts end,, I finally used a small vice & clamped the breach down to the tube (compressing the small o ring Im sure),, lo & behold,,, the tiny allen screw we all hate (LOL!!) was so loose I was able to tighten it a turn or two. Then,,,, BINGO,,, the gap between the brl. & tube was consistant all the way!! I installed the band back to factory position & tested again,,,,,, WOW!! This thing was grouping now!! Not like my 2260,,,,, but,, better than the "China Springer" groups I had been getting!! :D (Certainly decent enough for hunting) Then,,, I built my own muzzle break for it,,, BINGO,, one hole groups!! 8) (Cant explain why that helped further,,, "harmonicks" I guess??) I can honestly say,,, I now get one hole groups @ 25 yrds. now bench shooting w/ 14.5 Super Domes. :D Im only getting around 835 fps,,( I think maybe the "smushed down" seal is constricting airflow some??) Im not saying Im right about what I just said,, I am saying I put ALOT of time into testing my Lil Disco,,,,, this is truly what I found,,,, it worked on mine. Sorry for the long whinded post,,, just wanted to share my personal experience with what I also consider to be the best bargain PCP gun out there!! Tim. PS,,,,, my trigger still SUX!! :p