What is this for?
 

This is a specific design, so its got to be for some reason.

I've always wondered, tried researching online with no success and never asked due to embarrassment but I have had enough, my curiosity is killing me.

What is this thing?!?!

http://img404.imageshack.us/img404/2161/99602283.jpg

Bayonet lug.

It's for mounting an m9 bayonet
http://www.m9bayonet.com/images/rra-mid-m9bayonet.jpg

They still put these on todays m4's?

Jee, I would have never guessed.. Thanks man, now my curiosity has been fixed.

I suppose this thread can be deleted, or tossed under the others lol.

I feel much better.

glad you will be able to finally get some sleep.

a link to an article that was in our off topic AV'd section: http://www.reddit.com/tb/oiqap

http://airsoftcanada.com/showthread.php?t=135286

"Have some of this"

Heh, Classic.

Seems bayonets still have their uses

Why would you ever get rid of the spear in combat?
I mean if zombies are coming at you, I'd rather have the knife on the end of my gun than in my hand lol