I just put one one my .300 win mag. I decided I needed a different one from the Thunderbeast Brake that was currently on it. I put the TBAC on because I am waiting on a suppressor that is a thread over brake and decided it would be easier to just run their brake. The TBAC brake is pretty ineffective on a .300. It is only a two port design, I think three works much better.
I put about 50-60 shots downrange this weekend with the new Area 419 on there. It is MUCH MORE effective than the TBAC. I was easily able to spot hits and stay on target, which is the most important to me. I also like the fact I can get the adapter for my suppressor when it arrives and just thread it right on the adapter piece for the 419. The modular capabilites of the 419 are handy.