no 1st hand experience, but the reviews I have read of this gun say 1. there is a change in POI with brake "on" and "off" and 2. accuracy better with brake "on". I would be leaving it "on" anyway as it will make that 7 mag a little more comfortable to shoot. and as you know and as everyone is saying, you really will cause immediate hearing damage blasting away with a braked gun and no hearing protection on.

and what darkker is saying is right on point. turning brake on and off will affect barrel harmonics, which WILL change bullet impact.