Complete C-45 Pistol Lower -- SBA3 Pistol Brace

New Frontier Armory

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3.40 LBS
C-45 Pistol Lower
Pistol Cal
Black Ano
Magazine Type:
Glock Style
7075 Billet Aluminum

C-45 Pistol Billet Lower Receiver -- Glock Style Mags


Other Specifications and Features of the C-45 Complete Pistol Lower Receiver:

  • Machined from 7075-T6 aircraft grade billet aluminum
  • Matte black hard-coat anodized per Mil 8625 Type 3 Class 2
  • Precision machinedmagazine well with beveled feed lip for easy mag swaps
  • 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 different pistol caliber uppers
  • Includes factory installed MILSPEC Lower Parts Kit (LPK), stock kit, 8 oz buffer and SBA3 brace-- Ready to pin to your upper and shoot!
  • Compatible with most standard AR-15 components 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)
  • Threaded bolt catch pin (Threaded hole and hardware)
  • Integrated large opening "winter" trigger guard
  • Proprietary magazine catch assembly and ejector is included and installed at the factory
  • Manufactured to MILSPEC (where applicable) on state of the art CNC equipment for consistent quality parts and exacting tolerances
  • Save money by building your own AR-45 rifle from the ground up exactly the way you want it configured and shoot for less!
  • *Due to the force exerted on the BCG with a blow back system, there is a high likelyhood of breaking the bolt catch when activated by the LRBHO feature. New Frontier Armory is not responsible for sending replacements as this is not a warranty issue.

**NOTE – Please read the FAQ below regarding adjustment of your ejector before use and ensure you re-assemble with Loctite or similar threadlocker to prevent screws from backing out over time.


QUESTION: Do I need to adjust my ejector?

ANSWER: Yes, before firing your new pistol caliber lower we suggest you adjust your ejector. Loosen the two screws holding the ejector in to where it becomes a semi-tight friction fit. Ensure the ejector is seated all the way to the rear and all the way down in the pocket. Close your upper onto the lower with the bolt all the way forward. SLOWLY cycle the bolt in and out about 1/4 of the way back a few times then let the bolt close all the way and tighten the ejector screws. They are cupped to get a good grab on the SS ejector, so only hand tight or you risk the chance of bending the ejector over. Any slight rubbing at this point will wear in the ejector after a few magazines are cycled through the gun. If you see excessive rubbing you can also file down the top corner on theleft side of the ejector(shooters left). At this point you should remove one screw at a time without disturbing the ejector location and add locktite to the screws and tighten them back down. This will ensure the screws will not back out over time.

QUESTION: What type of magazines will fit in this lower?

ANSWER: The lower was designed to fit and drop free factory Glocklarge frame pistol magazines. Although it accepts and shoots other aftermarket magazines some slight modification may be needed to get them to drop free from this lower because of the varying width measurement we have seen when checking these magazines to Glock factory specifications.

QUESTION: Do you offer a reliable last round / empty magazine bolt hold open (LRBHO) System for this lower?

ANSWER: YES --After watching several companies try and fail to incorporate a RELIABLE last round bolt hold open (LRBHO) system into their lower receivers we decided to take a different approach and will be incorporating our LRBHO technology (PATENT PENDING) in our matching upper receivers. After rigorous testing and hundreds of hours of research and development, we feel that this is the best option for LRBHO on a Glock magazine AR style firearm. Ourupper will be compatible with other manufacturers lower receiver that either don't have a LRBHO or you can scrap the non-working LRBHO out of your existing AR-45 Glock Mag lower and solve the issue of not having a 100% functioning LRBHO. 

QUESTION: What bolt carrier group will work with a Glock magazine fed AR-45?

ANSWER: You will need an AR-45 Bolt Carrier Group that has relief cuts to clear the Glock style magazines. 

QUESTION: Do I need to use a special buffer when I build my AR-45?

ANSWER: It is advised that you use an 8 oz or heavier buffer. Lighter buffers aren't safe to use in a blowback system with larger calibers such as the .45ACP and 10mm, and they may not feed some types of ammunition reliably without the added weight.

The New Frontier Armory C-45 Complete Billet AR-45 pistol 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! 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.

Weight: 3.40 LBS
Dimensions: 17.50 x 7.50 x 3.00 in

1 Review Hide Reviews Show Reviews

  • 3
    Pistol lower

    Posted by Martin weller on 3rd Jan 2023

    I experience fast shipping and a great deal when they had their sale! When I order this lower I was expecting a shockwave brace (as advertised). When I picked it up from the FFL dealer it had SBA3 brace on it. If you do your research SBA3 braces are expensive compared to the shockwave brace. Thank-you for the upgrade. Service was top notch. Gave this item 3 stars. Reason is the mags are tight from the coating so I will have to do some sanding and polish to make the mag slide in and out without grunting. The mag release also sticks and rubs on the lower when trying to release the mag. Those 2 problems are a easy fix with fine sandpaper and polish. I have not test fire this lower. I'm still waiting and foaming at the mouth for a upper to come back in stock. Will come back and give this 4-4.5 stars if everything works flawlessly.

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