Bushmaster and DPMS are made in the same plant by the same people. As far as we can tell ther may be one difference between the two and that's the trigger guard.
RRA is a very old design that has matured. Being that there is no milspec for these I dont think you cant fault any manufacturer for tryng to improve a design or make it their own. After all Armalite AR-10 is the grandfather to all of these. As this 308 platform is evolving we are seeing progressive changes that will mean even less parts compatability. In my opinion folks need to clear their heads of these being AR-15's with regards to part swapping and think of them more like the different platforms that they are. Nobody buys a FN SCAR expecting major parts compatability with a Remington ACR or an AR-15. Heck DPMS is still changing stuff on the fly. We have Remington 700's and Winchester Model 70's, Chevy Corvettes and Ford Mustangs. It's all good and gives us options. jmho
Within the past few weeks they shipped me two LPK's for $15, an LPk, buffer, buffer spring and buffer tube for $10. Interestingly in 2009 they charged $20 shipping on a BCG. I wonder if they insure the orders or something
Im seeing this at several sites. Im at the point now where I often run simultaneous shopping carts to final checkout. I then decide where to order. SI Defense once refunded most of my shipping because they felt I was over paying on shipping ($12) for bolt catch screws.
There is a lot more gas with the .308. This will erode the block quicker than on a 5.56. That said, if your a casual shooter and a hunter it's probably nothing to worry about.