I just tryed out my new clamp on from Witt Machine
what a bargan.
I put it on a Savage 111 in 7mm rm. When I fired it I put my rifle on my rest and just fingered the trigger without holding the rifle, it barely moved. And I found that there was no "extra noise". The load I use is 67.0 grn IMR7828 cci mag primer 150 grn sptz.
I recommend this if you are in the market for a muzzle break that you can install yourself. The instructions on how to mount it are flawless. Each one is made for single rifle, when you order it you have to caliper the dia at muzzle, and 1&1/2 inches from the muzzle