• Skip to main content
  • Skip to primary sidebar
The Loadout Room

The Loadout Room

Professional Gear Reviews

Hardcore Gear and Adventure

Menu
  • Shooting
        • Pistol
        • Pistol Accessories
        • Rifle
        • Rifle Accessories
        • Shotgun
        • Machine Guns
        • Air Guns
        • Ammunition
        • Optics and Sights
        • Weapon Lights
        • Tips & How-To
        • Concealed Carry
        • Holsters
        • Suppressors
        • Precision Rifle Shooting
        • Firearms Training
        • image-112d3d00Helwan Brigadier 9mm Range Report
        • Photoroom_20250525_074933Juggernaut Tactical Frame Review: The Best Upgrade for Your 365
        • m142Too Tough to Die: The M14
        • craft holstersCraft Holsters Makarov Tuckable IWB Holster Report
    • Close
  • Gear Reviews
      • Mission Gear
      • Camping Gear
      • Survival Gear
      • Medical Gear
      • Adventure & Travel
      • Knives & Tools
      • Overland
      • Disaster Preparedness
      • Footwear
      • Womens Gear & Clothing
        • ac65a540-2ef3-4598-8d11-afdf53f46e94.__CR0,0,970,600_PT0_SX970_V1___Streamlight ProTac Rail Mount HL-X: A Thoroughly Bright Review
        • Bluetti 2 handsfree power backpackBluetti Handsfree 2 Review: The Ultimate Power Backpack for Off-Grid Adventurers
        • The Gallagator 10 day pack on the shoreline next to a hiking trail.Day Pack – Mystery Ranch Gallagator 10 – The Best Yet?
        • PXL_20240209_171721326Pic of the Day, It’s Graduation Time
    • Close
  • Men’s Lifestyle
      • Fitness
      • EDC
      • Eyewear
      • Watches
      • Electronics & Technology
      • Downtime
      • Mens Clothing & Accessories
      • Manly Skills
      • Style & Grooming
      • Gentleman Drinks
      • Crate Club
        • Photoroom_20250525_074933Juggernaut Tactical Frame Review: The Best Upgrade for Your 365
        • craft holstersCraft Holsters Makarov Tuckable IWB Holster Report
        • rs3CIVIVI RS71 Review : Big Blade Energy
        • civivi2Civivi Brazen Review: The Best Budget EDC Knife under $75?
    • Close
  • News
  • Video Demo
  • Buying Guides
  • Shop
  • Advertise
Gear Reviews

Convert Your AR Lower into a Pistol Caliber Carbine: Stern Defense Uses the Magazines You Already Have

August 15, 2019 by Mark Miller Leave a Comment

Stern Defense makes great AR magazine well adapters which turn your AR Lower into a Pistol Caliber Carbine. There are several models available which accept Glock magazines (9mm/.40), Beretta magazines (9mm) and two S&W M&P magazine versions in (9mm/.40 and .45 ACP). The latest version, the MAG-ADMP9&40/P320 , uses both SIG P320 magazines and S&W M&P magazines.

These adapters are very sophisticated. They lock in hard with no wiggle after adjustment. They hold your mags in and drop them free. Unlike some other PCC’s, the bolt hold open works every time.

The .45 caliber adapter uses the excellent S&W M&P magazines.

With the gun ban scares over the last few years and the popularity of 80% lowers, most of you reading this have AR lowers in a closet that you never built. Here is the excuse to build the pistol caliber AR you always wanted. If you only have one AR, in one minute, you can change the upper, buffer and add a magazine well adapter. Boom, new gun.

If you have a registered full auto lower, Stern gives you caliber options. Short Barreled Rifle? Why not blast pistol ammunition? If you have a 9mm suppressor, there is no better host than a 9mm AR. These conversions provide more fun for your training dollar.

This excellent Stern Defense video shows the 9mm kit, installation and full auto firing. I have worked several AR conversions, but there is nothing quite like the Stern Defense system. I got their MAG-AD9 conversion kit, with adapter, complete 9mm caliber upper and their 11 ounce carbine buffer.

The Stern adapter fits snugly into the magazine well and adjust in three axes with Allen head screws. This is what plugs into your magwell. You can see the magazine release sticking out to the left. Photo courtesy of Stern.

Read more at Paragraph4.media

Featured Photo: The pistol pictured above has the MAG-ADMP9&40/P320 with MOD4 4” M-LOK rail and  4” BARREL 9MM PISTOL UPPER KIT  MSRP $609.46 attached Nikon P-Tactical SPUR Reflex Sight

Photo by Mark Miller

Share This

About the Author

Mark Miller is a Green Beret who served in Afghanistan and a number of other live fire locations. He's a poet-warrior in the classic sense, a casual hero and a student of science.

See All Mark Miller Articles

More From The Loadout Room

Comments

Primary Sidebar

Most Read

  • Mossberg 930: the affordable 12 gauge auto-loader
    Mossberg 930: the affordable 12 gauge auto-loader
  • Helwan Brigadier 9mm Range Report
    Helwan Brigadier 9mm Range Report
  • ARES Watch Company Diver-1 & Field Watch: Unstoppable Tactical Watches for Land & Sea
    ARES Watch Company Diver-1 & Field Watch: Unstoppable Tactical Watches for Land & Sea
  • Removing Rust From Firearms? No Problem
    Removing Rust From Firearms? No Problem
  • Civivi Brazen Review: The Best Budget EDC Knife under $75?
    Civivi Brazen Review: The Best Budget EDC Knife under $75?

Find Us on Facebook

Recent Comments

  • Ajita Sherer on Vakarian Plate Carrier Review: Elite Comfort and Modularity for Under $300
  • Josiah on Vakarian Plate Carrier Review: Elite Comfort and Modularity for Under $300
  • Woox Store on Tommy Gun Madness: The Thompson Submachine Gun

Latest From SOFREP

News

SOFREP Evening Brief: Chaos Erupts at US-Backed Aid Hub in Gaza; Ukraine Detains Alleged Russian Informants, Including Teen

Editorial

500 US Military Trainers Now Reportedly Operating in Taiwan

Military

Freedom Flyover 2025: A Sonic Salute Over Miami Beach

Coalition SOF

Soldier of Fortune: The Shadowy Legacy of SAS Veteran Simon Mann

Military Content Group

© Copyright 2025 Military Content Group · All Rights Reserved.

  • Privacy Policy
  • Terms of Use
  • Advertisers
 

Loading Comments...