I have two brakes by:
Ross Schuler
261 Victor Gust Drive
Mountain Home Idaho 83647
rem40xb1@msn.com
He makes them in .813---1"---1.250 they can be tapered in the rear but not turned down full length.
I have one on a factory Sendero in 7 mag and one on a DPMS LR308. I sent Ross the outside diameter of my barrels and he matched them perfectly. I asked a local gunsmith to thread my barrels and time the brake. I have experienced significant reduction in muzzle jump and felt recoil. A lot of folks may wonder why I would brake a gas operated 308 but spotting my own shots improved dramatically.
With your barrel being pre-threaded you will either have to have a gunsmith time the brake; or spend some time working the rear of the brake over sandpaper until it aligns properly; or use a crush washer.
The best part is the price... when I bought mine last year they were $45 delivered... and delivered within a week.
I am not associated with this company in any way... just an extremely happy customer :)
Here is a thread from another web site that has been running for several years. You may find answers to other questions you may have in this thread. Have fun!
Matt
http://www.snipershide.com/forum/ubb...478267&page=12