• Machined from 7075-T6 aircraft grade billet aluminum
• Precision machined magazine well with beveled feed lips for easy mag swaps
• Machined to be compatible with 45 and 60 degree short throw fire control selectors such as the BAD_ASS ST 45 Lever
• Compatible with all standard AR-15 components and most aftermarket parts
• Take down pin spring and detent hole is threaded for a 4-40 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!

The New Frontier Armory 80% Billet AR-45 lower receiver is proudly MADE IN THE USA by hard working American men and women.

THIS IS NOT A FIREARM "NO FFL REQUIRED " CAN SHIP DIRECTLY TO YOUR HOME!!

All GCA and NFA rules apply when you complete this project. Please ensure you fully understand your local and federal laws before completing this 80% blank into a functioning receiver. New Frontier Armory will not be held responsible once this blank is altered in any way.

C-45 Lower Receiver FAQ:

QUESTION: What jigs can I use to complete this 80% lower?

ANSWER: Because of our mag well design, any jig that attaches to the REAR of the mag well will work for completing this lower. Other jigs can be modified to fit around our mag well and will also work. We sell a jig that works with all other 80% lowers on the market including our C-4 and C-9, and C-45 80% lowers.

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

ANSWER: The lower was designed to fit and drop free factory Glock large frame pistol magazines. Although it accepts and shoots other aftermarket magazines (Promag, KCI, Kahn, etc) 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. Our upper 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-9 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-9?

ANSWER: You will need an AR-9 Bolt Carrier Group that has relief cuts to clear the Glock style magazines. New Frontier Armory can also modify your Colt style AR-9 BCG for you to work properly with Both systems. More details on that service (coming soon).

QUESTION: What LPK will work with this lower?

ANSWER: Any standard AR-15 LPK will work. You will not need the magazine catch assembly, bolt catch roll pin, or trigger guard that are normally included with standard LPK's.

QUESTION: Do I need to use a special buffer when I build my AR-9?

ANSWER: Although its not technically required, it is advised that you either use a 9mm buffer (longer and heavier than carbine) or a spacer in your buffer tube before you place your spring in. The reason for this is to limit the BCG travel to the rear so it doesn't come back forward and smash the bolt catch hard enough to break it. The 45ACP BCG is shorter than a standard BCG. You can use a carbine buffer with a spacer or simply stack between $1.25 - $1.75 of quarters in your buffer tube.

QUESTION: It seems as though my BCG may be hitting or rubbing the ejector on the lower, how can I fix that?

ANSWER: Loosen the two screws holding the ejector in to where its a 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 the left side of the ejector (shooters left)