I hve a surefire M3 millenium combatlight that I was thinking of mounting to my M4. WOuld the handheld millenium be able to take the abuse of a weapon mount? If so how do you propose mounting it? Right now all I have is the RRA M4 upper...no sort of mounting rails so I need the whole setup. This is a duty gun that rides in the trunk so the mount needs to be pretty solid. Ideas please?

I am about to do the same thing. I was looking at an M96, but just cant bring myself to buy the extra light right now. I am putting mine on the bottom of a fout rail gas block. I will probably mount it in the Fobus light attachment, I thought about using scope rings, but I don't want to tear up the light. With the M3 and the Fobus light mount, I can also take the light out with no problem and have a handheld.

I called Surefire today, and they said it can take the recoil, as the bulb is shock isolated.

Sure it is, but the batteries aren't.  If you unscrew the head of an M3, the batteries will pour out.  If you unscrew the head of an M96x, the batteries are retained in the tube body.  Surefire recommends the use of their 9v battery sticks in the M96x, although not many use them.

The M3 will likely work fine, but if this is anything but a range rifle, go with the M96x.

That said, I used a non shock isolated 6P for years with no problems.

Okay, so there is a difference. I thought there might be.