Well Im looking to mount one of these at 9 o'clock on my M4. I have a Surefire M500A on so that limits my space for mounting. I will either be mounting the laser off my Barrel or off my FS. Would you recommend an ITAL for Side mounting or would an OTAL do just fine. I am thinking of going with the OTAL if I have room to mount it on top infront of my TA31F, but not sure if there will be room. Any thoughts or opinions is appreciated.

I think both of those require a rail to mount, the M500 does not have one(at least mine don't). maybe you could mount a rail, but I doubt the handguard is stable enough to hold a meaningful zero. The OTAL is designed to mount behind the front sight base (on the handguards), ITAL can go other places, but still needs a rail.

I think Laser Devices makes other lasers designed for your situation.

Let me clarify,

This is what I have mounted on my Barrel:

http://www.bushmaster.com/shopping/bmas/yhm-639.asp

I wont be mounting anything to the M500A, Since well you cant. Im just curious which would be better for this 9 oclock Mount, an ITAL or OTAL.

I don't think it makes a whole lot of difference when mounted on the above setup...ITAL vs. OTAL

OTAL has more applications, if you ever get rid of the M500 and get a railed handguard.

Just my thinking...