I run an M20 Olight R2 with an upgraded smooth reflector on my AR15. It throws light out to 275-300 meters. The new M20s have XP-G gen 2 LED's which throw 25 meters further and 100+ lumens brighter. Torches that were designed for pistols just don't do it for me for rifle applications.
The Streamlight TLR series are awesome. But I would spend my money on the slightly older TLR LED's that have a 100 lumen output and floods well for my pistol or shotgun. Use the extra money for an Olight or equivalent, for my rifle I want an LED that is meant to throw light down range so I can clearly see what I'm shooting at, at a distance.
About 150 bucks in 2 weapon lights and 5 bucks for a viking tac mount for the rifle.
(tested Olight against Fenix TK series & PD series, a couple surefires and Stream lights. Overall preferred the Olight m20 with the AR15 for quality, size, price, brightness, beam quality, throw, etc.)