just curious how strong most of these light weight rails are.

i assume the Larue & KAS FF RAS types are the strongest and heaviest but how are the Centurion C4/CMR and Geissele, DD M4, etc and dealing with a drop?

that military test with the mlok vs keymod got me thinking about this and the pics of the broken mounts was enlightening.

No. Then again I don't drop test or abuse my rifles in that manner. I just shoot the piss out of them and toss them in my truck bed. No issues.

Literally like 5-6 threads up from yours in this forum.

http://www.ar15.com/forums/t_3_12/713970_My-Geiselle-Mk4-Doesn-t-Like-Abuse--edit--A-Wild-GACS-Appears-.html

As for the others?  Breaking them to the point where they're falling off the rifle is pretty much unheard of.  The only rail I can recall that had issues was the original blended alloy KMR, which would crush/deform and have pieces of the metal snap off under hard usage, but it never broke away from the barrel nut.

Basically, you've got nothing to worry about.  You're not going to be able to beat up a modern "slim" FF handguard enough in normal usage to get it to fail.

yep, that got posted the same time i posted this. kinda weird.

although, his situation seems disingenuous and troll'ish.

If you read through that thread, Geissele does a "drop test" of sorts which is about the worse case scenario for most civilian end users and the rail performs fine.

You're going to be hard pressed to break most quality FF rails.