Jeremy with Kahntrol Solutions attended one of our long range shoots yesterday...
I told him he could demonstrate the product to any shooters who wanted to try one on their particular rifle.
He measured each muzzle diameter with calipers, and retrieved the correct fitting brake from his gear case.
I don't know how many he sold... but NO ONE took one off their rifle after he installed it and let them try it. Everyone who tried the brake bought one... including yours truly.
It's a good, effective product that allows you to brake a non threaded barrel without any trouble. Kahntrol also manufactures threaded brakes for rifles which have threaded barrels, and they're considerably less than the clamp on brakes.
I know this is an old thread, but since the subject matter is the same, I thought I'd post here.
Dan