After looking at a SureFire M900A I noticed that there appears to be very little clearance between the bezel and the rail it attaches to.  I am now wondering whether the turbohead M900AB model has enough space to fit under the rail.  This would matter little on a carbine because the light hangs off the end of the rails, but on a rifle it would be uncomfortable to have the pistol grip out that far.

Am I correct that the AB model must hang off the end of the rail system or are my eyes deceiving me?

I don't think the M900 fore-grip light will work on the rifle, either the A or the AB.  When I install the M900A on my Colt M4, I notice the barrel cast a shadow at the 12:00 position of the light pattern, the shadow is not that bad, there are enough light for me to ID the target and surprise the target on the receiving end.  For close range CQB work, it work fine.

On the other hand, I can imagine a much more pronounced shadow cast by the handguard, when the M900A was mounted on a 20" rifle.  It might block out enough light that render your light pattern useless.  I think one of the Surefire 9 Volt (I like the 9 Volt system because I can use the light all the way up to 200 yards) MU or Classic weapon light, mounted at either 3:00 or 9:00 position might work better.  I have a Classic 9 mounted at 3:00 position for my ACOG equipped M4.  I also have the bezel as far forward as possible to minimize the effect of shadowing.

leungken

I was in the process of buying one of these when I found that they mention no-where to have a lockout switch for deactivation of the flashlight.  

I would never want a foregrip with a pressure pad switch and no lockout.  

That light is great for mout but try flashing it inadvertently at night in the woods (posssible cause of death in a tactical situation)

Yes, the new M900 does have a lock out switch, it was the battery cover.  
I have an older model that did not have a lock out switch, and when I sent it back to Surefire for some warranty work (bad wiring), they replace the battery with a lock out one, for free.

leungken

Correct !!

A observation also with the M900 and weapons lights in general mounted under the barrel during a practical rifle night match last weekend, was if from your shooting position if crouch down as if using cover from behind a barrel in this  case  the light was blocked by anything in its path that appreared slightly lower than the target even if target was many yards further away.Those with 3 and 2 O'clock light positions had no problem.this might not be pertinent to CQB but definitely lesson learned for match shooters.

The lockout switch is an option, it is not stock.  See the online or paper surefire catalog for details.  It is not clear from the web site unless you down load the catalog.  One thing I didn't really like about the lockout was it wasn't labeled.

Incorrect, the lock out tail cap on the M900 is a stock feature that comes on all M900's. Some of the first ones released did not have the lockout tail switch. Not long after they began production, they updraded the cap to the lockout design, and it has been standard issue on M900's since. The lockout tail cap is visibly and obviously different (most noticable longer) than the older non lock out design.

True dat.  I have one of the newer versions that came w/ the newer version tailcap.  There's no need for "labeling" on or off; it's a 90 degree rotation either way & is easily discerned in the dark.

I know the space is needed for batteries, but the M900 is about 1.5 inches too long for me.
Using 20 rounder from prone it will probably interfere.

Or am i wrong ?

Yes, it will interfere, but I normally replace mine w/ the Harris when shooting prone.  When practicing from prone w/ the M900A on the rifle, I've learned to "lean" it enough to the left to clear the light & a 30 rounder.

Why bother to lean?  Just mono-pod on the handle, and put your palm in the middle as a "soft" pad.

leungken

You are correct
[img]http://photos.ar15.com/ImageGallery/IG_LoadImage.asp?iImageUnq=2698[/img]

It didn't seem to lower my profile enough - I like to practice shooting from as many awkward positions as possible.

Thanks Boland.

If I have to lower my profile, I used role over prone, which places the rifle "flat" to the ground, in either ejection side up or down position.  Of course, when shooting from the ejection side down position, place a palm between the weapon and the ground, so the spent case have a place to go.

You know, life sucks, and worse of all, sometimes cover and concealments sucks worse. [:(]

leungken

F_dA,
You are very welcome.




I am a little confused where the extra hand is coming from ???

I think he means to leave a gap between the rifle and the ground ???