I have a few .300 SBR's and I also have an Aero lower and couple uppers in the box (PM me if you interested in those, I'll let 'em go for a good price, just don't need 'em anymore). The lower is used some but very little, however, it does come complete minus trigger and buttstock.
With Form 1 rifles, I tend to use LMT, Noveske and now KAC lowers. Why? One guy pointed out why pay $200 tax on a $50 lower, that an SBR with one of the higher end lowers will be worth more down the road. Who knows? Most folks don't sell their NFA stuff so I guess you should use what floats your boat, but I'd use quality regardless. I don't plan on selling, but do like the idea of registering those vs. others.
As for the build, I've used nothing but Noveske barrels in .300BLK's and it's because 1. They work --they are reliable with supers and subs even with an 8.5"bbl. 2. They are accurate, generally 1MOA more or less, depending. 3. They're durable. 4. They work. Didn't I say this already? Can't be emphasized enough, they work with supers and subs, 110's to 220's (240's depending on twist) even mixed in the same mag. When I called Noveske, they wouldn't tell me the method for or the exact dimensions of the gas port in order to achieve this. This must be where they did their leg work. It would seem to me that given the .300BLK's attributes, that the barrel is more important than ever, because not only is it responsible for most all of the accuracy, it's now plays an integral role in the reliability of the functioning of the weapon.
Oh, I do have a 16" AAC upper I got a few years back. No complaints about it really, but it's also 16". I've heard short .300's can be finicky if the barrel isn't just so, which accounts for a lot of the adj. gas blocks I imagine. Wish I knew more about the other barrels but I honestly don't because once the Noveske performed the way it did, I never bothered to try anything else. Not for .300BLK SBR's anyway.
I have a recipe that works for me, I won't go into it, but the barrel and BCG account for what's important so the rest comes down to ergonomics and personal preference.
I use a TBAC Ultra 5 myself with an MVB stock and it functions fine, even with mixed supers and subs in the same mag. No adj. gas block, just the pinned gas block that comes with the Noveske barrel. I do use JP Ent. carriers and sometimes bolts on most all my rifles. The full weight JP carriers are by far the best I've used, slick as snot and really help with the reliability of the weapon.
Maybe i will keep an eye out for a noveske setup..
