I purchased a complete 16" PTAC mid length upper with a 1:7 barell on the black Friday deal. It was delivered on time, and with the nice weather I finally got it out to play with it. Fit, and finish is fine. Shoots well, and cycles no problem. I do have one MAJOR issue with this upper, and it seems to be an odd one. The rail on the upper seems to be out of spec, and seems a bit narrow. I have an Aimpoint Pro that I tried to mount on the rail. With the stock Aimpoint mount, there is a knob you turn and when it's tight you click it 3 more times for proper torque. When I place the Aimpoint on the PTAC upper, it is visible that the base of the Aimpoint is about 1mm wider than the PTAC rail. I can tighten it down, and the wedge on the mount bottoms out on the Aimpoint base, but the PTAC rail being narrower does not allow the clamp to grip the upper and it is loose.
I tried the Aimpoint on a Rock River upper and it tightens down just fine, and there is no visible difference between the base and the RR rail. I then tried it on a Colt upper and that one also was the same as the Aimpoint base. The PTAC upper has the "Square" forge mark, and I am happy with the rest of the upper. I just want to be able to mount the Aimpoint on this without having to drop another $150 for a different aftermarket mount. Is there something I can do to get this right?