That's where the cup holder is suppose to go 
Cup holder. Please I need a link. Next war I will be back in the bunker protecting your women.
ProjectGuns did the leg work and helped me get the 5.45 upper.. The ammo is cheap..
He helped me with the light hookup. He did not tell me about the cup holder damn it. :biggrin:
j4. All kidding aside. My ammo 5.45 has not come in yet. But me and my neighbor were checking out the mags. Except for the internals. I really think if you changed them out. That they are interchangeable.
The top of the mag where the bullet sits. It cocks the .223 sideways on the second round down inserted.
I bet it is the same damn mag with different internals. What say you guys. Hell I dont know.
Mall Ninjas rule.
For shooting over fences!!!that is a periscope!!