Sorry about this late reply, but I have gotten behind on my Graybeard reading. I have tried a number of brakes, but favor those made by custom gunsmith Darrell Holland for one reason. They are designed with a solid bottom, which means they do not kick up dirt dust, or rip holes in your pack when using it for a rest. I have them on my 45/70 rifles and on my .35 Rem. XP-100, and they are as effective as any brakes I have used.
Some 'smiths do not like them because they are a little more trouble to fit. I sent mine to Hollands, and have been 100%+ satisfied. Just MHO. They are available from Hollands, or through Brownells.