LW-4 Stripped Polymer Lower

New Frontier Armory

(6 reviews) Write a Review
0.51 LBS
LW-4 Lower
Black Polymer
Magazine Type:
Any standard AR-15 magazine

LW-4 Stripped Polymer Lower Receiver

Manufacturer: New Frontier Armory

Model: LW-4

The New Frontier Armory LW-4 polymer lower is the strongest polymer based lower receiver ever made. It is manufactured using Nylon 6, a glass filled and chemically coupled nylon polymer for maximum durability and strength.This will be the perfect lower for your AR-15 build to make it extremely light and incredibly durable. We have a lifetime warranty on our lowers to back that up.

    • Extremely durable with glass filled nylon-6 reinforced polymer construction
    • Accepts all MIL-SPEC and standard AR-15 parts and upper receivers 
    • Utilizes a square nut that seats in the pistol grip boss to provide a stronger, more durable attachment of the pistol grip (screw, washer and nut included!)
    • Lifetime warranty on all our lowers
    • Half the weight of an aluminum lower
    • Weighs only 4.15 ounces

NOTE: Castle nut should be installed with a maximum torque specification of 20 Ft Lbs. Damage can occur to receiver if excessive torque is applied to castle nut.



Don't forget to check out our Polymer LPK to keep your build ULTRA Lightweight and avoid voiding your warranty!! Find them by CLICKING HERE.


Q: Can I build myupper while attached to the lower receiver?

A: NO!When assembling your upper receiver DO NOT torque the barrel nut or muzzle brake while the upper is attached to the LW-4 (or any other model) lower receiver. Assembling the upper improperly could cause damage to the lower receiver and will NOT be covered under the factory warranty.When assembling an upper you should use a reaction rod or a vise block specific for assembling upper receivers.

The New Frontier Armory LW-4 Stripped Polymer Lower Receiver is proudly MADE IN THE USAby hard-working American men and women.


This is a serialized item considered to be a firearm by BATFE. This item must be shipped to a Federal Firearm License (FFL) holder. All BATFE, GCA & NFA rules apply! This item must be shipped to a Federal Firearm License (FFL) holder. You will be prompted at checkout to pick an FFL to ship to in your area using our FFL Locate tool.YOU will be responsible for checking with your local FFL to ensure this weapon is legal in the state that you reside and that they will accept this weapon on your behalf and transfer it to you.New Frontier Armory, LLC will NOT be responsible for any shipping or admin charges incurred by packages not being accepted by the FFL you choose during checkout.

Weight: 0.51 LBS
Dimensions: 9.50 x 4.50 x 2.25 in

6 Reviews Hide Reviews Show Reviews

  • 4

    Posted by Brad on 1st May 2024

    All was great except out of the 4 I ordered 2 of the buffer tube threaded ends were warped . So when cycling the gun the buffer spring was pushed against the inside of the tube causing it to shorten the cycle and not load another round. Thanks to milwaukee m18 heat gun and common sense I straiten it and cycling consistently now . But all is good for the $ you save and weight. Jtm poly lowers had a worse problem .. 2 were non usable.

  • 5
    Great product - dumb customer (me)

    Posted by LH on 16th Apr 2024

    Either I used a spring and detent the receiver didn't like, or the channel for the spring wasn't drilled quite deep enough/there was leftover material in the channel. I choose to blame myself in this case as I've dealt with both latter issues before without it ending this way. Either way, my front takedown pin (Strike ultralight) became completely jammed in place, fully inserted, after installing it the first time. The detent was so securely fixed in the takedown pin that I couldn't even begin to back it out with a hammer and punch, and I was entirely unable to push the detent down to attempt to spin or push the takedown pin out. After an hour of trying to non-destructively remove the takedown pin, I gave up and hit it with a wrench. Long story short, the pin is out and my receiver is in pieces. The receiver felt and looked great. It was light and strong and didn't feel cheap in any way. I feel awful about destroying something someone put time and skill into more than I feel bad about not getting to build another rifle. The slick sided upper I ordered with the lower is also awesome. Just without a home for a while due to my own actions. I've built a handful of ARs in the past without any major issues, so I don't feel like I'm completely incompetent. I sure felt like it this time though. This particular project wasn't meant to be, I guess. Maybe I should've just used the polymer detents instead of trying to use the ones I normally favor. Sorry guys.

  • 5
    LW -4 stripped lower

    Posted by Chris carbine on 30th Sep 2023

    I like polymer while the upper receiver is aluminum ,it's all good for personal civilian use, I'm not in a war zone? where the aluminum upper and lower is needed , everyone has their preference ?

  • 5
    LW -4 stripped lower

    Posted by Chris carbine on 30th Sep 2023

    As expected when I ha so called "10 day cooling off" time frame , it's all good, I got the products I ordered tho hA THANK YOU NFA

  • 4
    Mostly satisfied

    Posted by Mark on 11th Jan 2023

    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

  • 5

    Posted by kayakjeenyus on 8th Mar 2021

    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!

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