How does the DDM4 rail compare to the RIS II?

[RAM Engineer]

Since the RIS II rails are unobtanium without paying a premium these days, how does the DDM4 (picatinny) rail compare to it?
Looks like the same barrel nut, but less bolts and the bolts are button-head instead of socket head. Obviously, the RIS II has a removable bottom section, whereas the DDM4 is a single piece.

[joeyjoe]

I own two DDM4/LITE III 12 inch quad rails. They are installed on two different BCM uppers. In short, they are my favorite quad rail on the market. I really like the dimensions of the RIS II, but i actually prefer the profile of the DDM4 rail. The DDM4 is the lightest quad I've ever held and i really appreciate how tucked in all of the rails are. You are correct in saying that the bolt up plate is very similar between the two designs. 4 bolts instead of 6 and they are facing the opposite direction. I imagine that the bolt up system on the RIS II is slightly more robust, but I've not had any issues with my DDM4 rails coming loose. Its hard to know how robust a mounting system is without constantly beating guns up against trees. I don't do that, but it seems to me that the DDM4 rail system is more robust than most designs. There is virtually no rail flex, as the rail itself is very rigid. If you are going for a clone, you need to stick with the RIS II. However, if you are looking for a quality quad rail i would definitely go with the DDM4 rail. I was hopeful that the new BCM quad rail would be similar to the DDM4 rail, dimensionally, but its not. the BCM rail is noticeably fatter and bulkier. Its a shame because i really do like the BCM bolt up system. Personally, if I were looking for a quad rail today, id go with the DDM4/LITE III.

FYI, if you do go with the DDM4 rail, pick up some extra bolts, as the stock bolts are a bit soft. Ive not experienced any issues regarding function etc, but if you plan to take the rail on and off, you may end up stripping the stock bolts.