It started life as a firehawk. A very short M4, slightly over pressure to make up for its insane ROF (yet to be clocked properly).
The firehawk comes with a sound AMPLIFIER and this worked too well, it was loud to the point of pissing me off quite a lot. Due to its extra cylinder volume i doubled the barrel length to gain a bit more power and maybe a little accuracy with a tight bore cut down to the length of the stubby suppressor.
Is it silent with the suppressor/barrel extension instead of the amplifier? Hell no, but quieter to the point i can fire it all day without feeling like i had my head in a metal bands\' drum kit.