Buy one for a 22 caliber and have it bored out. They are most effective when they are the right size. You should know that there is no free lunch...the muzzle brake will stop things like recoil and muzzle rise but it comes at a price that to many shooters is just not worth it. The terrible back blast you will get might cause you to flinch. Sure, ear protection will stop it from popping your ears but the shock wave of gas being redirected can be tough to get used to. The above posts even make it sound like the only one that wont like it is the guy shooting next to you...yep, and he is second to the guy pulling the trigger when it comes to all that back blast!! Who is closer, you or the guy ten feet to your right?? To me, I would rather just take the recoil and if it's too much get a different gun. The whole muzzle brake concept sounds like "all ya gotta do" is put the thing on and enjoy no recoil and no muzzle flip with no consequences...but it don't work like that. You cant stand hunting with one unless you hunt with ear plugs. I will say that as claimed above the JP Eliminator absolutely kills all recoil. You could watch the bullet impact with a big heavy magnum...if you don't blink from the back blast. Already having threads on the end of a barrel can make it seem like the thing to do but, well...you can drive your car with you feet if you want to, but that don't make it a good idea.