Which host are you comparing the FRP on? Not doubting you, just curious. My ARC 22 is great on my 10/22 and FVSR, because it's very light. It's very quiet, but I don't think it takes much to quiet a 16" 22lr.
On my 22/45 lite, I have to hold the action closed on the first shot, seems to help, the FRP is loud!
I would love to hear a ARC 22/Mask comparison!
Original comparo was on a 16' 10/22 where the pop was less than the Spectre. My S&W 422 4" has a noticeable pop with both cans.