I have a aero M5e with .210 high. I read in one of the question that had to get a option to fit on the upper. What is the option or will it fit. — 2 Answers

If you have the M5E1 Upper Receiver then you HAVE to use Aero's M5 Enhanced MLok handguard (currently have paused production of the Quad rail version) due to the M5E(nhanced)1's proprietary barrel/handguard mounting system. If you have the M5 Upper Receiver (NOT the M5E1) then both the Aero M5 Atlas S & R models, the M5 Enhanced MLok (with retro fit adaptor barrel nut sold by Aero), and theoretically any DPMS/LR308 High Tang Profile compatible handguard should fit and line up with your receivers 12 O'Clock Pic rail...theoretically. According to JP's website, the DPMS/LR308 versions of the MK 3 Standard & MK 3 Rapid Configuration handguards are semi monolithic. This is because on their own they sit below your receivers top rail, but if you also purchase their purpose made pic rails (the 12 O'Clock model...different models for 3, 6, & 9 positions) and install them onto the MK 3 handguard then it will be in perfect alignment with your upper receivers pic rail. The problem is, they don't mention whether that's true for High Tang Profile or Low Tang Profile. That's as far as I've gotten in my research for my M5 build. I have an M5 upper & an m5E1 upper and am torn between building out the M5 with the mk3 rapid config or building out the m5E1 with the M5 Enhanced MLok... Lol decisions decisions. GL!