I like clamp on brakes. They work very well. Here is a review I did of the Kahntrol version. Do NOT severly over torque the screws, most a rated in inch pounds. First time I installed it I went over torque recommendation of 30 inch pounds, went to 50. Now I just do the 30 recommended, no problems with it loosening and no Loctite of any kind used..
Review
After looking at a number of Clamp on brakes I decided to order the Kahntrol brake. Even with exchange and postage it was cheaper than buying the Canadian equivalent. It was however quite a bit more money than the Witt Machine brake.
Kantrol KSMB645 for muzzle diameter of .640-.675 $149.95 U.S.
Witt Machine Exact fit to the barrel measurement $89.00 U.S.
Grizzly Exact fit to barrel measurement $235.00 Canadain
One of the big reasons I chose the Kahntrol was it was the only one that was able to fit on a fairly wide range of barrel sizes, in this case from .640 - .675. It means I can use it on more than one gun. All of the other brakes were cut for the exact muzzle diameter of the specific gun barrel, accurate to .003. This makes fitting them to any other guns unlikely.
Kahntrol accommodates the wider range of barrel sizes by having 6 vertical tightening screws along a horizontal split. Very similar to a set of scope rings but over a much longer opening.
The brake was very easy to mount on my Left Hand 26" all Stainless Remington 700 in 7 RUM. I followed the on-line instructions and had the brake mounted, levelled and timed in about 20 minutes. I could have done it faster but I was quadruple checking everything and being very careful to ensure everything lined up perfectly so there would be no chance of baffle strikes when fired. The one thing I did different than the instructions was torque it down to 50 inch pounds rather than the 30 recommended.
This 7 RUM is my all time least favorite rifle to shoot out of the box. It didn't really recoil in the traditional sense, it was more appropriately described as a REALLY SHARP punch that even with lots of padding would give you a headache after 10 or 15 rounds. Not really surprising when you figure you are burning 95 grains of powder behind a 162 grain bullet in a gun the weighs 8.5 lbs with scope. It was far more unpleasant to shoot than my 375 or even my 460. (To be fair both of those are quite are bit heavier and the 460 has a brake on it). In fact I have never shot any other gun that was as nasty to shoot or kicked as sharply as this 7 RUM out of the box.
After installing a Mercury suppressor in the stock and a Pachmeyer decelerator pad it was comfortable to shoot but still had a very brisk recoil and quite a bit of muzzle jump. I figured this made it the perfect candidate to try the Kahntrol Brake on.
In addition to the brake, I had also mounted a new Leupold 4.5x14 B&C reticle scope for an upcoming antelope trip so the gun needed to be sighted in as well. With everything mounted and two loads that I know shot well in the RUM, 162 BTSP with 84 grains of 7828 SSC in Rem brass with Winchester mag primers at 3.60 LOA, and the same with 94.5 Grains of Retumbo, I headed to the range. (Both of these loads are pushing the 162 grain Hornady bullet north of 3300 fps) It took two shots to get the gun hitting 3" high, dead on the line at 100 yards.
With the bake on there was no difference in group size or shape at 100 or 300 yards. Both loads shot just as good as before, making 3 shot clover leafs at 100 and under 1" at 300. There was however a VERY noticeable reduction in recoil and muzzle jump. The gun felt like something between a 223 and a 243. I checked the brake after the first shot and every two or three thereafter and there was no indication of baffle strikes, as it should be. There was however carbon buildup on the barrel and brake as the number of shots increased. I checked the bolts after 20 rounds and found no decrease in torque.
I was wearing muffs and plugs, as I always do at the range and I did not notice any increase in perceived noise from the brake. I was alone so I did not have anyone to validate whether it was louder to the sides but I would be willing to bet that like all brakes it is. Also, with the amount of recoil reduction it must be pushing a pile of gas to the sides so anyone shooting beside you will definitely feel the blast, though from previous experience this gun makes a hell of a muzzle blast off to the sides even without a brake.
After 30 rounds of very slow fire I felt no soreness in my shoulder nor any other ill effects of shooting, and all I was wearing was a T shirt. I then removed the brake and fired a two shoot group. It hit exactly 1.5" left but on precisely the same elevation, exactly 3" high, as when the brake was on. I adjusted the scope and fired a three shoot clover leaf group that is exactly 3" high, dead on the line at 100 yards. There was a very noticeable increase in recoil without the brake and no perceivable reduction or difference in muzzle blast or noise.
The brake is very well made and fits to the gun well. I would never use a brake on a hunting rifle but this is a great tool for working up loads on guns that tend to beat you up. I could see absolutely no differences in the groups but this is only one gun. I will be interested to try it on a couple of other rifles to see if the results are the same. If they are I will probably order a couple more to cover other barrel sizes.
It is completely effective in reducing recoil and making heavy or medium hitting guns into pleasant to shoot rifles. For range shooting it is the cats pyjamas and because it is so easy to mount and remove it is perfect for use on guns that are primarily hunting rifles as well. The POI shift is easy to adjust for when you remove the brake.
A number of folks asked me to post this after I got the brake and tried it. I hope the info is useful to others thinking about putting brakes on their rifles.