While I would also recommend a dedicated weapon light, both the M2 and M3 handheld lights employ shock isolated bezels. One advantage to these handhelds is that they can be cannibalized to replace broken or damaged parts on their sister weapon lights, M3/M500/M900 and M2/M95/M96, etc.
The mount for the M96 takes up quite allot of *real estate* on the handguard. We had a student in a class with one that had the tail cap with the pressure pad tape switch and between the light, mount and tapeswitch it interfered with his gripping the forend on a 16 inch barreled rifle. I had to loan him a click on tail cap that he activated with his support hand thumb (which worked out well).
IMHO, the M95 and M96 are fine light systems that would be more at home on a full length rifle or mounted to a gas block with a rail interface. Might also work at the six O'clock position but again, a dedicated weapon light is the better option.
Another issue to contend with is lumen output.
For indoor use, 6 volt systems provide plenty of light but outdoors, 125 lumens is the minimum I would want on a shoulder weapon and I ususally use the 225 lamp in my M500's. The downside to the brighter lamps is washout of reticles and red dots against a light colored wall or background. I run aimpoints on my rifles so in these situations I simply use the front iron sight as they are co-witness with the red dot.
HTH
Tony