[RemMax]

I know the RDIAS will work with both Bushmater Guns as well as Olympic Lowers, the Oly Lower has a Model1 Sale's upper on it
They will NOT Fit in a Rock River Arms Lower due to the Depth of the recess below the Rear Lug
As for the RLL, if I was going to spend the money on one of those I would think that modifying slightly any carrier I had would be a small price to pay. Just my thought on that.