I've been using my AR20 for about 10 months with no problems has yet.
Over the chrono the spread is 6fps pellets are jsb express 7.9
I found the rifle to be a little front heavy but with a little mod like butt hook it helps with the balance over all love the rifle
Daystate ftr/zelier 6x24x44
Hammerli / leup comp 40x with a jon harris cylinder and a mick tromans brake