I was searching for a spacers for my Comp m4s aimpoints to make them true lower 1/3 co witness. When using a Bobro or factory QRP mount, the aimpoint spacer does not make it a lower 1/3 co-witness. Took some ARMS #74 spacers that I milled out the center channel to match up with the aimpoint style spacer. No one, including Bobro, makes a spacer to achieve the true 1/3 height. So I set off to make my own… I am no means a professional, but have the means to do a little “custom” if you will, work. The channel in the ARMS mount would not work with the base of the Bobro or the QRP mounts. SO they had to be modified. To my knowledge, this is the only way to get a Bobro mount or factory QRP mount to the true lower 1/3 (SOCOM) height. Little bit of chatter making small tooling marks but the milled out slots are in fact perfectly flat.
I also took a offset mount and milled out the channel and then counter sunk the hole so the bolt head would sit flush in the spacer. Finally found a solution to my needs. Took a little time, but it was well worth it!
Height difference between factory aimpoint spacer and arms.
