i wouldnt say that RRA makes much better product than dpms. they both are far down on the list. i think both are tier 5 if i remember.
What is the tier system? Is that something someone made up?
The tier system has been around for sometime generally applies to manufactures and the product they produce.
Tier one generally applies to true mil-spec rifles that are tested to mil-spec standards and few problems exist with the final product: Colt, LMT, BCM, H&K
Tier two generally applies to manufactures that have few problems and build general quality rifles, however they may need some tweaking to bring to a duty standard (staking and chamber reaming): RRA & Stag are general seen in this tier
Tier three generally applies to manufactures that produce a AR-15 that is not build to Tier 1 or 2 standards and problems are found more consistently: DPMS and Bushmaster are typically seen in this tier.
You better take your jar of vaseline with you if you're looking to trade a used DPMS for a new RRA. I would just buy the RRA outright, and if you don't want the DPMS, try to sell it here.It's in a shop...haven't taken mine in yet to see what I can get in trade, was wanting to get opinions on here first. May just buy it outright and have both