Trixxeo

the gearbox isn't too dissimilar from a v2, other than the fire selector lol. there's a little tricky plastic star bit with divers on it, that a metal ball bearing sits in, this is the part that transfers the movement of the selector. I would look at that 1st.

Check to see if your gearbox hasn't cracked causing play. My specna box lasted 1 days and about 500 shots. Was an orion box

Some hopups require a shorter or longer air nozzle. Too long and it will not feed. Too short and you'll get multiple feeds. Also some aftermarket ones have washers and springs to push them back against the gearbox. The removal of the o ring can sometimes be the difference between feeding and not. But why change just because its rotary?

Safe handling ect can be done dry. As for target practice. Its an airsoft gun lol a fly farting will put the bb off course

Its most likely the hop bucking than anything. The notches in the barrel will stop it twisting.