C-4 Billet Lower

New Frontier Armory

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(9 reviews) Write a Review
0.00 LBS
C-4 Lower
Black Ano or RAW (Media Blast Only)
7075 Billet Aluminum
Magazine Type:
Any standard AR-15 magazine

C-4 Stripped AR-15 Billet Lower Receiver


Other Specifications and Features of the C-4 Stripped AR-15 Lower Receiver:

  • Machined from 7075-T6 aircraft grade billet aluminum
  • Matte black hard-coat anodized per Mil 8625 Type 3 Class 2 or RAW (media-blast) finish ready for Cerekote, Duracoat, and other custom finishes
  • Precision broached magazine well with beveled feed lips
  • Machined and engraved to be compatible with 45 and 60 degree short throw fire control selectors such as the BAD_ASS ST 45 Lever
  • Caliber marking of "Multi" so it can be used with many different caliber uppers
  • Compatible with all standard AR-15 components and magazines and most aftermarket parts
  • Take down pin spring and detent hole is threaded for a 6-32 set screw for easy capturing (hardware included)
  • Upper tension screw behind grip screw (threaded hole with hardware included) to adjust any “slop” out of vertical fit between upper and lower
  • Ambidextrous trigger finger rests with grooves (above and below mag release / mag catch)
  • Compatible with Norgon and other aftermarket ambidextrous mag releases
  • Threaded bolt catch pin (Threaded hole and hardware)
  • Integrated large opening "winter" trigger guard
  • Manufactured to MILSPEC on state of the art CNC equipment for consistent quality parts and exacting tolerances
  • Save money by building your own AR-15 rifle from the ground up exactly the way you want it configured

The New Frontier Armory C-4 Stripped Billet AR-15 lower receiver is proudly MADE IN THE USA by 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 during 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.

9 Reviews Hide Reviews Show Reviews

  • 4
    Varianced Lower

    Posted by Bret on 29th Apr 2024

    I really like these lowers, but apparently dealers can no longer do varianced orders for them!

  • 5
    C-4 lower

    Posted by Richard on 27th Apr 2024

    The C-4 lower is seriously the best bang for the buck! Great quality for the price

  • 5

    Posted by Mount27 on 8th Mar 2024

    Great product, as always. Cannot wait to do more business with New Frontier

  • 4
    C-4 lower

    Posted by Jacob on 26th Feb 2024

    I picked this up to match a c-4 side charging upper I had bought. Seems good quality unfortunately I bought a ballistic advantage barrel for this build before receiving the upper or lower and there is a lot of play between barrel extension and the upper. The barrel extension is spot on I think the upper is the culprit for the wobble I am having. But it’s probably (within spec) just a lot looser than what I am used to working with. Lower seems fine there is quite a bit of play between the upper and lower also the upper will rock side to side quite a bit. I have not finished this build yet because of the play with the barrel and upper.

  • 5
    c-4 billet lower receiver

    Posted by Phil on 6th Feb 2024

    Arrived in good condition, assembled with no issues or quirks with a Lower Parts Kit, and the fitment between all five of my uppers was great. (Did not need to adjust the upper tension screw at all.) This is not a negative, but one thing I noted was that the magazine well was slightly tighter than my other lower. It is not out-of-spec, it's just tighter - my polymer mags run absolutely fine, but some of my metallic magazines don't insert or detach as smooth. (This is the fault of the magazines, but if you're a person who runs a lot of dubious magazines, you may run into issues.) The one issue that may actually be a complaint for some people is the coloring of the anodize. It really is more of a dark gray than a true black. This bothers me none. But if you're the type of person who cares about the presentation of their equipment, you might be irked by all your "blacks" not matches. I'm a target shooter, and I bought this to assemble a dedicated lower for a 6mm ARC build. It's been great, with no issues, so buy with confidence.

  • 5
    Great lowers

    Posted by Quentin Swartz on 26th Oct 2023

    These Billet lowers are really Nice! The 2 threaded included screws put it over the top!

  • 4
    C4 lower

    Posted by Danny Lee Cornelius on 24th May 2023

    This is an awesome product. I will not be buying plain mil-spec lowers anymore.....i think NFA does a great job on quality and service. Thank you and I will be ordering more

  • 5
    Very well made lower

    Posted by Thomas Beckham on 6th Apr 2023

    I’ve used New Frontier lowers before and have been very satisfied with them. I was particularly pleased to find the Allen screw keeper for the takedown spring and detent was provided although I’d already purchased a supply of them.

  • 5

    Posted by jocole99@sbcglobal.net on 21st Oct 2014

    As a manufacturer of firearms, this is the best looking and most "user friendly" lower I've ever had the pleasure to work with. With the lower to upper tension screw, you can throw away those silly "accu-wedge" shims. The takedown pin spring set screw makes the assembly of the receiver extension a breeze. The threaded bolt catch pin removes the extra work and care required to set the old style roll pins without damaging the finish on the lower. Anti-walk trigger pins fit more exactly to the somewhat wider width of the lower's exterior dimensions. The select fire marking is great for those fire control drop-ins such as the Tac-con 3MR. New Frontier is a great company with industry leading innovations such as the side charge billet upper.

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