The info about the screen is in the books...20 mesh in the wrap and 30 mesh for the washers? I have info to that effect. Wish you could just drop in and go through this info...
That's where I went with this.
Yes, leaves very little for strength, but works like a hot damm...trying to bleed off the velocity. Works as well if you put the holes in the center portion of the barrel and keep 2" at each end for starting and stability.
I can't say I recall any mechanical noise. Just the jingling of empties on the concrete around me...300 in 15 minutes.
I found that continued use caused the stainless screen outside the gas bleed off holes in the barrel to be heated red hot by gasses and then it started to beat a hole in that spot. The baffles had carbon build up of course...as you'd expect. As you say, they aren't silent. Just doesn't sound like a shot.