I have the M6 on my .40 tactical. Its neat. There is one serious drawback which I am surprised more people dont mention--- It can only be zeroed in at one specific distance! Due to the distance it sits under the muzzle, the laser points upwards to some degree. As I recall, Streamlight recommends zeroing it at 25yards. Thats all fine and dandy, but at distances less than this, it will shoot low (several inches). This is very pronounced if you aim at say, 10 yards. Likewise, if you were aiming at 40yards, it would aim high.
If anyone has any insight into this, I'd love to hear it. Due to the discrepancies listed above, I dont think I would be totally comfortable using the laser dot in a critical situation (BG holding innocent and needing to place an accurate shot). That being said, it is useful for dry firing and seeing if you can hold a bead. Also, lasers do have a intimidation factor to them, but dont rely on it for aiming. The flashlight is by far the more useful tool and the laser doesnt add much to the size, so I can live with it. If I had to do it all over, I would probably get a M3x and call it good.
Anyone with a M6 care to comment on the zero "issue" and any thoughts>?