The rules allow you up to a 25mm x 75mm muzzle brake or a suppressor of any size as long as it only has one hole on the end, no ports.
Suppressors take lots of recoil & muzzle jump out of the firearm and are sorely tempting but the weight they add to the extreme end of the rifle make them "feel" more cumbersome. Although your rifle is rather short to begin with

A good muzzle brake is very effective too.
Get both with the same thread and swap between the two to choose - brakes aren't very expensive!
For your other question about multigun events - yes they can be run but aren't "officially" recognised by PNZ.
They end up being very long stages that take ages to reset and stage all the guns - but yes can be loads of fun

CAS boys & girls do multigun every weekend
