JP GMR-15 9mm Billet Lower Receiver Kit

JP upgraded their awesome GMR-13 9mm AR rifles with a new lower receiver that features last round lock back, an improved magazine release and a flared magwell. The new model designation is GMR-15. Fortunately JP has made the new 9mm lower available in kit form. The “JP GMR-15 9mm Billet Lower Receiver Kit JPGMR15LRK1” would be my choice for a 9mm AR build today.

From JP Rifles: For the home builder with a 9mm Pistol Caliber Carbine project, this GMR-15™ billet lower receiver accepts Glock G17 magazines and will mate to any Mil-spec compatible upper receiver. This kit includes all proprietary bolt catch, magazine catch and ejector components required for function. Read more about the GMR-15 platform here. Visit JP

ORION 9mm AR-15 | 9mm AR Lower | 9mm AR Upper

ORION 9mm AR-15

It always excites me to learn of new players and products in the field of AR-15 rifles, carbines and pistols. The latest to catch my interest is the Orion 9mm AR-15 product lineup. It’s common knowledge here on AR-15 TACTICAL that I completely embrace pistol caliber AR-15 carbines, especially those chambered in 9mm.

The 9mm cartridge  is standard issue to many law enforcement for use with duty sidearms, the United States Military M9 pistol and probably the most popular centerfire pistol cartridge in the world. This commonality guarantees easy to locate and inexpensive ammunition for shooters everywhere.

ORION 9mm AR-15 Product Lineup

Orion Guns offers a full line of 9mm AR-15 products that include complete 9mm AR-15 rifles, complete 9mm AR-15 upper receivers, complete and stripped 9mm AR-15 lower receivers and 9mm AR-15 barrels. What is not clear about Orion Guns is whether they actually manufacture any 9mm AR-15 hardware themselves or assemble hardware from other manufacturers. I suspect the answer is somewhere in the middle. The pictures on the Orion Guns website as well as the website appear to be home brew.

Judging from the pictures on the website I suspect Orion is producing 9mm AR barrels and combining them with hardware from other manufacturers as necessary. Nothing wrong with any of this. In fact I praise and encourage them for recognizing a void and diving in. Orion Guns must be doing something right because I learned of them from Brownells. Click here for more information and ordering.

ORION 9mm AR-15 Barrels

The Orion AR-15 Barrels Chambered in 9mm are available in 5″, 8″, 10.5″ & 16″. Made of 4140 Chrome Moly Steel and black nitride finished, these barrels are heat treated and stress relieved. They are stress relieved once again after the button rifling process. All barrels threaded 5/8-24 with a 1-10 twist.

ORION 9mm AR-15 Upper Receivers

Orion offers 9mm AR-15 uppers with the following barrel lengths, 3-inch, 5-inch, 8-inch, 10.5-inch and 16-inch. The uppers are available with knurled tubular, quad-rail and standard two piece A2 style handguards.


  • 5″ 9mm Orion Barrel
  • 1-10 Twist
  • Black Nitride
  • A2 Flash Hider
  • 4″ Ridged Free Float Tube


  • 8″ 9mm Orion Barrel
  • 1-10 Twist
  • Black Nitride
  • A2 Flash Hider
  • 7″ Ridged Free Float Tube


  • 16″ 9mm Orion Barrel
  • 1-10 Twist
  • A2 Flash Hider
  • Ridged Mid-Length Free Float Handguard

ORION 9mm Lower Receivers

The Orion 9mm lowers appear to be assembled to a price point. My preference would be a Hahn 9mm magazine block and KNS anti-rotation pins installed on the lower. Note use the KNS anti-rotation pins on all 9mm AR rifles. Visit our 9mm rifle project that closely resembles the Orion offerings

ORION 9mm AR Lower Specifications

  • Anderson milspec Lower
  • Promag 9mm Magazine Block
  • Made of 7075 T6 Aluminum
  • M4 6 position Stocked lower
  • Installed CMMG Lower mil spec parts kit
  • Buffer & buffer spring installed
  • Add $18.00 each for every 9mm 32 rd mag you want
  • Uses Colt pattern 32 round 9mm magazines (We use Bushmaster colt pattern Metal mags)

ORION 9mm AR-15 Bolt Carrier Group

Orion Guns offers a black nitride coated, standard Colt 9mm AR-15 bolt carrier group. The bolt carrier works with standard AR-15 hammers. The carrier is also Glock compatible. The bolt carrier appears to be CMMG brand.


Maxim Defense 9mm AR15 Stock

Maxim Defense 9mm AR15 Stock – CQB

Maxim Defense 9mm AR15 Stock – CQB stock built for comfort and durability for real-world use. No buttons to push, just pull the stock to deploy. At its most collapsed position, this CQB stock only adds 5.35” to your AR15. At full extension, the Maxim CQB stock is the length of an extended carbine stock. And with 4 total positions you can adjust for maximum comfort and multiple scenarios. Rapid deployment, purpose driven materials, and the functionality you need, the Maxim Defense CQB Stock is simply the most thought out, versatile, and durable CQB stock on the market. Includes the 9mm specific JP Silent Captured Springs which has been

Maxim Defense 9mm AR15 Stock Specs

  • FEATURES: Extended Cheek Weld, Easily installs on mil-spec AR15 lowers, Interchangeable Buttstock Assemblies
  • WEIGHT: 18.59 oz.
  • MATERIAL: 7075 Aluminum Alloy housing for optimal performance with QD mounts
  • LENGTH: 5.375” closed 6.875” 1st position 8.375” 2nd position 10” fully extended
  • BUFFER: Standard, Heavy, and 9mm weight JP Silent Captured Springs. Standard and Heavy weight Buffer & Spring.


Built in Sling Mounts, 7075 Aluminum Housing

The Maxim PDW Stock features built in anti-rotational sling mounts on each side of the stock housing. Both the housing and the stock are made of 7075 aluminum for maximum strength to weight performance.

Length of Pull Preset & Steel Guide Rods

With the “grab and pull” operation of the Maxim Defense PDW Stock, you may want the stock to stop in the same position each time it’s deployed. Install the provided set screw and you can have consistent length of pull every time you expand the stock. 3/8” Black Nitride Steel guide rods for strength and stability.

Knurled Collapse Lever

One hand operation is possible with the Maxim collapse lever. The take down lever is knurled for positive gripping when hands are wet or wearing gloves.

9mm AR15 Trigger | 9mm AR 15 Trigger

DPMS Trigger and Rounded Un-Notched Hammer Suitable for 9mm AR15 - 9mm AR15 Trigger

DPMS Trigger and Rounded Un-Notched Hammer Suitable for 9mm AR15

9mm AR15 Trigger

The 9mm AR15 Trigger is easily where the most confusion lies with the 9mm AR platform. My own research was met with a lot of “Should work” , “Most 2-Stage” and similar vague answers. One of the problems is most AR15 TRIGGER manufacturers have not tested their triggers in 9mm AR15 rifles. The other problem is there are two different kinds of 9mm AR15 BOLT CARRIERS, ramped and un-ramped. We will get into specifics below.

I would like to take the mystery out of the 9mm AR15 TRIGGER. Please use the button below and share the specifics of your build.

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Note 1: I use the term “BOLT CARRIER GROUP or BOLT CARRIER” which is not entirely accurate when discussing the 9mm AR15. Technically speaking the 9mm AR15 utilizes a “BOLT“. I use the term “BOLT CARRIER GROUP  or BOLT CARRIER” because that what many shooters are used to referring to in an AR15.

Note 2: This page is a discussion of AR15 HAMMERS and AR15 TRIGGERS in 9mm AR applications. The conversation gets more complex when a .223 5.56 AR15 UPPER RECEIVER and a 9mm AR15 UPPER RECEIVER will share a common LOWER RECEIVER. That’s a topic for a different day and page.


AR15 TRIGGERS with a “Rounded” M16 profile are required for 9mm AR15 RIFLES with RAMPED BOLTS and 22lr AR15 Rifles.

Heres is what we know for a fact about 9mm AR 15 TRIGGERS.

9mm AR15 Trigger featuring a RRA 9mm AR15 Hammer

RRA 9mm AR15 Hammer

  • Dedicated 9mm AR15 Hammers like the ROCK RIVER ARMS RRA 9mm HAMMER part# 9MM0106 must be used with UN-RAMPED 9mm AR15 BOLTS



To be continued…




The most common 32 round 9mm AR15 magazine got it’s start long ago when 32 round 9mm UZI magazines could be had inexpensively just about anywhere that sold such items. Depending on the 9mm conversion unit used there was a choice of modified or unmodified UZI magazines. The Colt 9mm Carbine and Rock River Arms 9mm AR both use modified Uzi magazines. The Hahn 9mm conversion block also utilizes the modified UZI magazines. Olympic Arms used to offer a conversion block to utilize Sten magazines. I do not believe that is still an option from Olympic Arms. Olympic Arms also offers a 30 round 9mm AR15 magazine that is their proprietary design to common their .40 S&W, .45acp and 10mm variants. This design has nothing in common with the UZI and UZI inspired designed.

Note: While I refer to the magazines in this section as 32 round I do so as that is their original design. As I write this there is lower capacity magazines available for those shooters not permitted by law where they reside.


The ASC 9mm AR15 MAGAZINES cost one third of the Colt branded 9mm AR15 magazines. Translated $20 versus $60. I own quite few of the ASC 10 round and a couple 32 round capacity. The function flawlessly and appear well made. They are not quite as heavy as the comparable Colt models. Interpret that how it suits you.

ASC Stainless Steel 9 MM magazines are an improvement on the Colt style classic AR magazine. Engineered with the highest levels of quality for confidence and 100% reliability, simply the best in the industry!  Our magazines are manufactured  100% start to finish in the USA formed out of 410 Stainless Steel Alloy .052 gauge for superior strength and  lasting endurance.  Our magazines are chemically treated for corrosion resistance [ref QQ-P-35] integrated with our proprietary coating, a high grade Marlube which is a wear-in not wear-off coating that burnishes in the surface providing self-lubricating properties.  The interior dimensions of OAL 2.316” ± .002 are perfect for reloads.  From first to last… rounds feed flawlessly through our 9 MM magazines.


  • Chrome Silicon Springs
  • Enhanced Anti-tilt Polymer Followers
  • 410 Series SS Retainer Plate and Floor plate-  Powder coated Matte Black


Brownells is a recent entry in the 9mm magazine market. I have no personal experience but they review very well.


  • Rugged heat treated steel magazine body
  • Durable steel follower
  • Matte black Xylan coated magazine body
  • Xylan coating drastically reduces friction and provides excellent corrosion resistance
  • Bolt hold open tab
  • Easy to remove floorplate allows for quick maintenance and cleaning
  • Round count indicator windows allow for a quick assessment of remaining ammunition
  • Fits AR-15 rifles that accept Colt style magazines




Rugged, all-steel, high-capacity magazines for 9mm AR-15 conversions that use a Colt-style magazine. Metal follower won’t distort under a full load and aids smooth, reliable feeding. Hold-open feature works with ARs fitted with hold-open on the conversion block. Easy-to-remove floorplate makes disassembly fast and simple. Fits Colt, CMMG and Rock River conversions with a lower receiver conversion block.


Rugged, high-capacity magazines are designed for 9mm AR-15 conversions like Colt and Rock River Arms that use a Colt or modified UZI magazine. Polymer model has a lightweight, reinforced molded polymer body that resists damage if dropped on a hard surface and has deeply molded grasping ridges to give you a firm hold when inserting the mag into the rifle. Steel model has traditional, all-steel construction, with numbered witness holes that let you make a quick check of remaining round count. Both have an anti-tilt follower to aid in smooth movement of the round stack for reliable feeding. Removable floorplate for easy cleaning. Requires a lower receiver conversion block, available separately.






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