Great optic fit for my m&p fpc - Patriot Optics Double Tap 1x30mm 2 MOA Red/Green Dot Sight

Out of the box, the Double Tap was impressive. Very "tactical looking" and all of its controls are placed for intuitive operation.
The optic is easily mounted onto the top rail of my FPC, but here is where it lost one star from me. When folding the FPC, it soon became apparent that the oversized mounting knob wouldn't clear the top of the chamber area of the rifle, which led to me having to move the optic further forward on the rail. It's totally not a game changer as i do intend to mount a magnifier behind the Double Tap anyway. However, if i preferred to keep it mounted further back on the rail, I would have to remove it or move it every time i folded or unfloded the FPC. Not a very convenient thing to have to do. I am considering replacong the knob with a wingnut or other fastener that will allow the sight to clear the chamber top.
The optics are very nice and having the option of either red or green dot is a plus. The laser works well also. Today I will head to the range to sight it in and test everything out under fire. I am expecting to be pleasantly satisfied with the operation of the Patriot Optics Double Tap.