Anyone have any thoughts on the mounting systems for the Surefire X-300? If I get the -A, will I be pissed when I find it won't mount to anything? Which is sturdier?

In particular, this light (or one of several) could end up on a P320, a SIG 1911, a P220, a Glock 19 (have both a G3 and a G4, if that matters), and an AR and an MPX.

On at least one of the ARs, the light would be mounted on the 12 o'clock rail fore of the front sight. On another/on the MPX, it will probably be either 3 or 9 o'clock on either a rail or via keymod/mlok rail section.

If you're putting it on a Glock, go with the A model. It seems as if Surefire had Glocks in mind with this mount. Marriage made in Heaven.

If you want versatility, like mounting the light to a rifle rail, go with the B model.

The A models lock in place and that's that. The B model- well, I've never had it happen with mine, but that screw could loosen and back out enough to lose the light. It would have to really loosen a lot for that to happen, though. The A model simply seems more secure, that's all, but the B model is more adaptable to different rails.

Here' an old pic of my G17 house gun wearing an X200. The pistol still serves as my house gun and now wears an X300A.