I have a friend who owns a nice walnut S400 carbine fitted with a muzzle brake with still air cone in .177. At the game fair this weekend he bought a silencer adapter and SFS silencer from Tony at SFS. He came to my house today so I could fit them for him and zero the rifle. I put the silencer on and immediately checked it over the Chrono....685fps with 8.4jsb. I adjusted the rifle but could only get 715-720fps spread over 10 shots with the side port adjuster wide open. just for peace of mind I replaced th muzzle brake and the power was back to where I set it a few weeks ago...780fps. Does anyone here think that just by fitting a Silencer the power would drop by around 100fps. I checked for accuracy and it was drilling holes at 30yds so its not clipping. I have experienced this before, but not by such big margins.