I am going to keep this initial post somewhat short, but I hope to get back to add more tomorrow.

I am putting together an SPR build to add to the collection. I wanted to put my old 15" MI quad rail to use and replace it with a troy alpha rail on my main AR. The more I scroll through the MK12 Mod 0, 1, H  thread the more "inspired" I become. The question at hand is which brake I should go with for this build. Obviously I am not looking to put together a clone when Im using a 15" rail for the build, but I am strongly considering the Ops inc brake and collar seeing as I will be ordering a WOA SPR barrel. It almost seems like a crime not to put something on that step. I really like the look of the surefire brakes and from what I've been told it would to a much better job at actually taming the gun. As far as suppressor use goes I am currently living in MN and as such wouldnt be affixing a can any time soon, but both of these options are adapters either way. Im somewhat worried that my rail would cover up the collar on the Ops inc set up anyway because on the 16" barrel its covering now the rail ends about 1/4" from the crush washer on my comp. I cant say I know exactly how far back the collar would go in comparison. If the Ops inc set up was cheaper I wouldn't think twice, but its $50+ more for something that would seemingly give me worse performance. To be honest I feel like the brake & collar system is a lot about looks on this build, but I really like the look of the surefire adapter as well.

Probably going to be piggy backing my order with another guy, so Id like to decide soon - hence the hasty post - I guess I just want some opinions so you guys can make the decision for me :)

Thanks.

Pictures for reference on the 16" barrel. Could the added diameter of the barrel / collar on the WOA barrel be an issue as well? I could always run the rail without the end cap, but would prefer it keep it if it wouldnt interfere.

I own both having a Mod 1 and a Mod h and a Surefire break on a couple of my other guns.  If you're not going to build a clone or a suppressor I would get the Surefire break.  If your going to be shooting indoors, under a covered awning, or next to friends I would perhaps go for a flash hider.  They do tame the gun, but lets be honest, there isn't that much to tame.

I would imagine from this picture that the end of my rail would be over the collar. The specs on the rail is 15-3/16".

*Crickets*

Anyway, I hope I dont regret this too much in the long run, but I think I will be going with the surefire mb556k.

Being that it is already a bastardized setup and the rail will cover at least some portion of the collar I dont think its worth it to spend the extra coin just to go for "the look".