Recently purchased my first flat top AR15-----all my other AR's have 'fixed' Carry Handle uppers----and, I also purchased a new two-lever ARMS #19A Channel Mount to use in mounting a TA31 ACOG.

I am having trouble mounting the ARMS mount to the flat top rail:  When I go to mount the ARMS mount so that the two levers are to the left, the ARMS channel mount will slide onto the rail until a black plastic piece stops the mount from moving any further forward---it also seems to prevent the reinstallation of the charging handle and bolt carrier, etc.  Is that normal?  I assume that I am supposed to remove the black plastic piece------right?  If not, what am I doing wrong?

Also, when I go to mount the ACOG to the ARMS mount, I assume that I am NOT supposed to use that little 'wedge' that is used with carry handles to obtain a snug fit between the screw and the bottom of the carry handle-----right?  Just use the screw and the washer----right?

Thanks!

None of the mounts (SLIDE) onto a rail, they tilt on. The cross bar is a stop, so no way was it made to slide into a notch, doesn't work that way. There are no plastic parts on a 19 Acog.
The levers do not open to the left, they open in oposite directions and close and lock towards the center. Suggest you go to a gun shop and have some basic info demonstrated about mountings, eye relief, etc.
Jack

Welcome back Jack!!!

Quoted: Welcome back Jack!!!

+1

Thanks for the comment/help, Jack.

As I look at it more, your'e right---what I am calling a black plastic part is, in fact, metal and the spacer that must fit into the cuts in the Pict. rail---it, accordingly, must tilt on, not slide on.  Will try it tonite.

I understand the basics of eye relief already.  Thanks again for the assistance!

Quoted: Quoted: Welcome back Jack!!! +1

+2