How are you guys mounting X300’s to your guns?
I’m pondering trying it at the 9 o’clock position and the very front of the rails.
Like this:
The setup on mine is the same as spamsammich’s!
Another 12:00 fan.
I tried it there for a while, but ended up putting it back on my G-19.
My duty M-4 has no rails - just old school handguards. I spent $20 on the CAA triple rail piece that bolts to the holes in the plastic handguard. X300 rides at about the 10 o’clock position. I love it to the point that when they offered me a railed forearm I said no thanks. 
Light, simple and it’s in the perfect spot for my support thumb to activate it. I can still lay my rifle across a piece of cover to steady it w/o worrying about blocking or damaging the light.
I’ll try to get some pics to post this week.
12 o’clock since Jan/Fed 2008…
I like the 12 oclock as well. Works well strong side or weak side when transitioning.
12 O’Clock for me as well.