08-16-2012, 02:12 PM
I don't think you're going to see any benefits of billet vs. forged as long as the mass is there, the material is 7075 or 7000 series Aircraft-grade aluminum, and hardcoat anodized deeply into the aluminum like a Type III Milspec. The DPMS Lo-Pro's might be 6061, as they were before IIRC. I think I've seen distributors market them as 7075, but who knows for sure.
6061 is softer, and is easier/cheaper/faster to machine. I'm not sure if the 6061 upper will gall with continued recoil over time enough to make POI shift or cause accuracy degradation. Bill Alexander's understanding of metallurgy and the characteristics of the Grendel would have to weigh-in on that one, but we can see what he uses on the long-barreled guns to gain a clue.
6061 is softer, and is easier/cheaper/faster to machine. I'm not sure if the 6061 upper will gall with continued recoil over time enough to make POI shift or cause accuracy degradation. Bill Alexander's understanding of metallurgy and the characteristics of the Grendel would have to weigh-in on that one, but we can see what he uses on the long-barreled guns to gain a clue.