Hey everyone I am building an a r15 and need some help. I really would like to put on the new haley strategic kmr 15 http://www.bravocompanyusa.com/BCM-KMR15-Free-Float-Handguard-p/bcm-kmr15.htm on my gun. My buddy says I would need to buy a new gas block and just cutting down the front sight block wouldn't work. What gas block would work for this system? My upper is a 16in bravo company http://www.bravocompanyusa.com/BCM-16-Mid-Length-LIGHT-WEIGHT-Upper-Receiver-p/bcm-urg-mid-16lw.htm

You can cut down your fsb if you're comfortable grinding on your upper, lots of people do it.
http://www.ar15.com/forums/t_3_118/566557_Cutting_Down_A_Front_Sight_Base.html

Anything low profile will work if you want to buy one. BCM sells one since you're already shopping there. Just make sure you get the .625" size since that's what the upper you linked has. You'll have to get the pins out of the existing fsb, which can be a stone cold bitch sometimes.

http://www.bravocompanyusa.com/BCM-Low-Profile-Gas-Block-p/bcm-lgb-.625.htm


The 15" also hasn't been released yet to my knowledge.

There's no reason that you can't shave your gas block down enough to fit.