Hi Zack
I have had mine for about a month now and agree with your observations. The sweet spot on this gun is between 175-160 bar, after this, the velocity drops like a stone. The first two mags will give a consistent spread of about 30 fps but if you go another two, it will drop another 100 fps. In the sweet spot, I am getting around 45 fpe, 42 fpe, 43 fpe and 39.5 fpe from the 25 g monster, jsb jumbo heavy, Barracuda 21.14, jsb exact jumbo 15.9. All these pellets work well. I have also observed that the barrel does not like being cleaned and takes about 200 rounds for the groups to tighten back up. This gun is marketed as a hunting rifle but it weighs as much as a sniper outfit. Mine is around 13 pounds with scope and bipod! The barrel weight is extra baggage and does not improve accuracy, but if you remove it, your P.O.A will probably shift about 1.5-2.5 inches at 50 yards. I hope these observations are of use to you and anybody else considering buying one of these behemoths.