Oh yeah, I forgot. I've also experimented with the Madbull HUTU. Works remarkably well if you're too lazy to build one.
Not quite as bright as a silencer unit but it did the trick.
I wired mine to a 9v battery stored in my handguard and had a momentary switch mounted on the front hand guard either at my front thumb or index finger so that I could actuate it when required. I also had a mini 3 position toggle switch wired in so that I could set it to 1) power the momentary switch, 2) HUTU power always on, or 3) off to power it down for transport, as I noticed the momentary switch would often get pressed when in my gun case resulting in a depleted battery the next game. lol
using a HUTU in conjunction with a silencer (or tracer unit) helped suppress some of the flash out the front. being able to flip on the silencer unit allowed for a much brighter full auto burst down range when you're not particularly worried of return fire. (eg firing for effect)