Picked up one of their 17" .22lr uppers during the recent sale based on it being advertised as "compatible with standard AR15 lowers" - turns out that doesn't include the MARS-L.

Right-side bolt catch is pushed outwards by the bulge behind the brass deflector, resulting in binding of the bolt due to contact with the bolt catch.





I'm at a loss regarding what to do about this. I realize another lower is always an option but I have two MARS lowers dedicated to (mainly SBR) conversions.

Looks like you just need a modified paddle to clear. Could it be cut halfway through and tig welded at an offset angle?

Customer service tested fitment last week, and you're correct; the contour of the new upper and brass deflector aren't compatible with a MARS-L lower.

Yeah, big OOF on this one considering how popular LMT lowers are. Probably will have the same issues with similar ping-pong paddle ambis.

Ordered two new lowers just to run the 4 uppers I picked up from CMMG. Went with an ADM since it's ambi with the right-hand bolt release configured horizontally, and a FA lower.

I've always sung their praises on every PCC thread and love my Banshees, but spending another $2k for this oversight, after parts and stamps, has soured me a bit.