MVB Industries AR-15 Pistol Caliber Billet Upper Receiver

Picture of a MVB Industries AR-15 Pistol Caliber Billet Upper Receiver

MVB Industries AR-15 Pistol Caliber Billet Upper Receiver

The MVB Industries AR-15 Pistol Caliber Billet Upper Receiver, Stripped, is the perfect platform for building your unique, mission-specific, 9mm, .45acp, 10mm and 40S&W AR-15 pistol caliber rifle/pistol. Made from a high-strength, 7075 T6 aluminum for durability. Mil-Spec, MIL-A-8625 Type III hardcoat anodized finish adds extra strength and delivers superior abrasion-resistance for rugged field use. Precision-machined to ensure drop-in installation of Mil-Spec, aftermarket components. Weight 7.8oz.

Will also work for .22 AR-15 rifles and pistols (AR-22)

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MVB Industries AR-15 45ACP Magwell Adaptor

Picture of a MVB Industries AR-15 45ACP Magwell Adaptor

MVB Industries AR-15 45ACP Magwell Adaptor

MVB Industries AR-15 45ACP Magwell Adaptor is designed as a drop-in accessory for a standard AR-15 lower receiver and uses a standard H&K USC 45 caliber magazine.

Will not work with the New Frontier Armory .45ACP bolt, as it has geometry that makes it incompatible with the feed angle of H&K USC pattern magazines.

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New Frontier Armory C-45 AR-45 Stripped Billet Lower Receiver

Picture of a New Frontier Armory C-45 AR-45 Stripped Billet Lower Receiver

New Frontier Armory C-45 AR-45 Stripped Billet Lower Receiver

New Frontier Armory C-45 AR-45 Stripped Billet Lower Receiver Features and Specifications

  • Machined from 7075-T6 aircraft grade billet aluminum
  • Matte black hard-coat anodized per Mil 8625 Type 3 Class 2
  • Precision machined magazine 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
  • Compatible with most standard AR-15 components  and most aftermarket parts
  • Takedown 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!

Frequently Asked Questions: Source New Frontier Armory

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 the left side of the ejector (shooters left).  At this point you should remove one screw at a time without disturbing the ejector location and add loctite 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 Glock large 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.  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-45 Glock Mag lower and solve the issue of not having a 100% functioning LRBHO.  For more information on our matching Pistol Caliber Upper, please CLICK HERE.

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.  Our Standard .45 BCG can be found here.

QUESTION:   What LPK will work with this lower?

ANSWER:  Although we sell a specific LPK with just the parts needed to build the C-45 lower receiver HERE, 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 LPKs.

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.

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The Foxtrot Mike Products Extra Heavy Pistol Buffer FM-45 has internal Tungsten weights, to improve cycling of any blow-back operated AR-15 .45 pistol caliber carbine action. With its extended length, the FM Extra Heavy Pistol Buffer requires no spacer and helps prevent bolt catch breakage.


By installing this buffer, you’ll enjoy smoother function, less felt recoil, and reduced rate of fire from your AR pistol. The FM Extra Heavy Buffer is compatible with all 9mm and 45 caliber upper receivers. Foxtrot Mike’s FM Extra Heavy Pistol Buffer is the secret ingredient to make your AR-15 pistol reliable and smooth-cycling.

  • Perfect for a 45 Caliber PCC build
  • Compatible with all blow-back Pistol Caliber upper receivers
  • Long duration, deep penetration Salt bath Nitride Melonite/QPQ finish gives lubricity and wear-resistance
  • Extra Heavy 8.0 oz. (pistol) weight
  • Extended Length, improves cycling
  • No need for a spacer
  • Made from Premium 4340 Steel
  • Made in the U.S.A.
  • Manufactured with ISO:9001 and AS:9100 quality certifications
  • Extra weight reduces felt recoil in all PCC’s
  • Increases dwell time for all trigger groups, aids in proper function in any Pistol Caliber AR Build
  • Comes standard with (2) heavy internal Tungsten Weights
  • Internal weights help with “bolt bounce” and improves reset on all triggers


AR15 Carbine Buffer vs AR15 45acp Buffer

AR15 Carbine Buffer vs AR15 45acp Buffer -

AR15 Carbine Buffer vs AR15 45acp Buffer

AR15 Carbine Buffer vs AR15 45acp Buffer – I like to be very visual in my explanations. One picture truly is worth a thousand words. In the picture above a standard AR15 Carbine Buffer is compared to a Heavy Buffers .45acp buffer. There is probably nobody that understands the AR15, AR10 and 308AR recoil system better than Slash at Heavy Buffers. The Heavy Buffers .45acp buffer at eight and a half ounces is a half ounce heavier than the eight ounce Hahn AR15 Pistol Caliber Carbine Buffer.  Slash also recommends a Wolff Spring #16501 for maximum reliability. Visit Heavy Buffers for more information.

Note: Slash dimensions are proprietary. That is why they are not listed.

AR15 Carbine Buffer vs AR15 45acp Buffer



I felt is might be useful for some to see the difference in the 45acp AR15 HEAVY BUFFER compared to a standard ARMALITE AR15 CARBINE BUFFER. In the picture below the mass of the AR 45 buffer is pretty obvious. The 45 AR Buffer also weighs in at 5 ounces more than a standard AR15 buffer. The weight difference comes not only from the size but from the material used. The AR15 Buffer is aluminum and the AR 45 Buffer is made from very dense and heavy stainless steel. Make sure you buy the right buffer for your 45 caliber AR15 carbine, pistol or rifle.




AR15 CARBINE BUFFER   – 3 OUNCES 3.250″ Long

.45acp AR15 BUFFER – 8.5 OUNCES 3.750″ Long


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