I have one in the Winchester M70 Classic Stainless. It's a great feature - accuracy can become superb and recoil is reduced, but, like a muzzle brake, it can be loud.
If your friend can't stand the added muzzle blast, then there used to be available (if there still is) a "BOSS" system without the holes. In this manner, you can still tune your loads without the added muzzle blast.
Zachary
If your friend can't stand the added muzzle blast, then there used to be available (if there still is) a "BOSS" system without the holes. In this manner, you can still tune your loads without the added muzzle blast.
Zachary