I would advise against that location, or even near the end of a suppressor. Usually having the end of the device more or less flush with the rail on most "long railed" carbines is a good location, as it allows space to index your thumb ahead of the "FIRE" buttons, so you're not resting on them in a "neutral" firing position, and you need a deliberate and distinct movement to activate the laser, while giving you easy access to the sliding switch when you're "indexed."
I know people do it with LED lights all the time, however with the MAWL in particular, you have a good chance of damaging the propeller selector if you're mounting it over the muzzle device, especially a compensator that will be directing blast right into it, not to mention carbon buildup on the emitter lenses.
~Augee