M4 25 cal tune

I’m shooting FX 34 Grain pellets out of a compact gun barrel 500. What could one of you Airgun masters suggest I tune this gun too. I’m at 860 shooting 25 grain now just like a heavier pellet. Be nice if someone could even point me to a nice video to see some visual.

also I was thinking of converting my M3 impact to the compact and making my M4 the longer version 700 because it’s the latest and greatest, but I like the fact that they removed the regulator is there a video that anyone knows of for the M3 impact removing the regulator. I present that to you as a question for you, Expert gunners thank you for your time.