I am using a Perun V2 Hybrid in a CYMA Platnium M4 with the 30k Warhead brushless motor, and an 11.1 1 100c brick battery. This CYMA comes with 13:1 gears. I am achieving 38rps on the ssg, but the fps is varied by up to 70fps. Approximately 7 shots @336-337, then two @407, then back to 336. I have very good compression and seals on all air components, gotta trust me here lol, despite what it sounds like. Also, it used to regularly shoot 420s, +- 2fps with .20g. I have never had this problem on lower speed builds, so it's definitely a stress situation. I am hoping it's not a problem with the high speed gears, high speed motor, insane battery, and Perun. The m4 Platnium has a unique sector gear. It a 12 tooth, but they made it with 2 missing on the front pickup side, and 2 missing on the back end. The timing lobe underneath is adjusted for this of course, but I wanted to include that detail in case there is something wrong here. My kid has basically the same build, but his battery only allows him to reach 34rps. No feed issues, very consistent fps @ +- 1.5fps. It rocks. I can't figure out the problem, but i think it's from a very slight PME? I don't see any wear on the gears tho. Probably 700+ rounds through it testing various adjustments so far? Perhaps the sector over spins just enough to catch the tappet before the nozzle can fully seal on the bucking. I know there is an AB problem between Warhead and Perun, but has anyone found some way to keep this from happening? Is my tappet spring too weak? I took off 2 wraps so far. That's kind of the last hope as I have tried everything else. Because this isnt a dsg, I haven't gone crazy on modifying the tappet fin or taking more off the tappet spring. Anything you can recommend?