This is the fourth polymer lower receiver I've ordered and the first from NFA, the others weren't worth keeping, but the quality of this lower receiver is better than the other polymer receivers I've tried, so I'll be keeping this one. The only problem I ran into with the lower was the hole for the safety detent wasn't drilled completely thru and the safety spun freely. I had to finish that hole and now the safety works fine. Regarding the lower parts kit: as recommended by NFA, I used their lightweight polymer parts kit, which turned out to be a waste of money, the qaulity of the parts kit was terrible. The safety was plastic and felt terrible, so I replaced it with a standard mil-spec metal one. I used the mag release that came in the kit as a standard mil-spec one fit too snugly in the left side of the receiver and would bind. the takedown pins were plastic and flexed, and just felt cheap, and the worst part of all was the trigger, which I had to video because I felt was unsafe. I could pull the trigger, hear and feel a click, but the hammer wouldn't fall, unless I applied more pressure to the trigger, which wouldn't move any further but would allow the hammer to fall. I was able to duplicate the condition with the upper receiver removed, and after the trigger click, the hammer would still hang up, but would drop if I bumped the receiver, or if I pushed the top of the hammer with a finger. NFA states the warranty on the lower receiver is void if I use a metal trigger and hammer, but their lightweight plastic one is definitely not staying in my receiver. I've reported this to NFA and offered to send the videos, but have yet to hear from them days after emailing them, I'll update later if they respond. Summarize: Lower receiver, 4 stars, pretty good. lower parts kit, 1 star, going in the garbage

I bought this to replace my polymer 80% lower that only lasted a year on my 300 blackout AR Pistol. I've had this carbon fiber lower for 2 or 3 years now and it is great.! and it is half the weight of my polymer lower. here are some lower weights to compare this to, my stripped billet lower weighs 10.4 Oz., my polymer lower weighs 5.86 Oz., and this carbon fiber lower only weighs 3.73 Oz! you will notice the weight difference when you switch to one of these. And it is plenty strong for the 30 cal. bullets I use. I use my AR pistol when camping in wilderness areas and hiking on the Appalachian trail. It is outside a lot and still looks and functions as it always has, if your looking to lighten up your AR, this is the best lower for the job. the bolt lever fits and works great on it too. unlike my Black Rain Ordnance Billet Lower, it doesn't clear on that. I build ar's and have tried several brands over the years, but this is the one I tell my clients to get. I only build side charging uppers and it's great for those too. the parts fit nicely and I have never had a problem with anything on this lower. this is the best and cheapest way to reduce the weight of your AR and it is super strong. Now I am slowly replacing the lower parts with titanium parts, and those can be expensive, but you don't have to buy them all at once, buy a few here and there and it doesn't take long to make this even lighter, comes in handy when carrying it in my back pack on the trails I hike. I will be buying more when they come back in stock. was hoping to buy one today but see they are out of stock. you will definitely like it so buy with confidence. New Frontier makes good stuff!