Not for all pdw's/sub guns - Aimpoint ACRO P-1 Red Dot Reflex Sight

Purchased this for my Sig MPX wanting as small a profile as I could get. Unfortunately the ACRO does NOT offer enough elevation adjustment to bring rounds on target with the MPX or my MP5 clone. Mounted the ACRO with the intended B&T 22mm mount and was unable to zero the optic where other red dots have zeroed perfectly.

The adjustment screws turns almost entirely freely with little to no noticeable click making precise adjustments slightly more difficult. I assumed something was wrong with my ACRO and contacted Aimpoint. They had me send it in but returned it saying it was in working order leading me to conclude this optic is just not intended for all PDW's or sub guns.

I write this as a US Marine with a lot of experience sighting in a wide range of optics.