I have a BRK MF170 on my 22" .22 Blackwolf. As it so happens, I just did a test with a sound meter recently. With the meter 7' away from the muzzle, A setting, and about 45 degrees off axis: No moderator, 78.8 dB Moderator, 65.2 dB That is a pretty massive difference. I only took one shot...