Back in the Saddle Again Subcompact Guns—Protecting Army Senior Leaders


By Major (Ret.) Walter Christian Håland

Staff Sgt Shawn P. Linhares, a Sierra Vista, Arizona native, 25th Infantry Division, surveys his surroundings as he and his fellow soldiers escort Iraqi Army Officials and 25th Infantry Division leadership through the streets of Mosul, Iraq.


Since World War II submachine guns or subcompact guns fell out of use in the U.S. Army in the subsequent decades; however, NATO allies continued to use submachine gun designs. “Sub guns” have long been used by special operations forces such as the Navy SEALs for close-quarters battle shooting scenarios. Now, the U.S. Army has decided to use subcompact guns once again.


This article presents the six sub guns that were prequalified, submitted sub guns and the winner, plus some of the other initial weapons offerings for the program.


Response to the RFI

A Request for Information (RFI) was posted May 2, 2018, to obtain information and feedback from industry regarding Sub Compact Weapons (SCWs). The chosen SCW is destined for the service’s Personal Security Details (PSD) personnel tasked with protecting senior Army leaders or other principals.

PSDs originated in the Iraq War to protect command personnel who traveled in less than secure areas. The U.S. Army intends to buy up to 1,000 SCWs, but that number could be expanded to wider use throughout the Army. These systems will require a potential contractor to be able to supply all components for the SCWs to include the weapon and accessories. The government sought the following information for planning purposes only.


General Requirements

  1. Delivery schedule of SCW to include but not limited to functional weapon, magazines, cleaning kits, suppressors, specialized tool kit (if required), spare parts, slings, carrying cases and manuals.
  2. Ammunition for SCW—Compatibility with 9x19mm military grade will be required.
  3. Sub Compact Weapon—The SCW will be a full-/semiautomatic selectable variant that has a MIL-STD-1913 Picatinny Rail.


The RFI also mentions the capability to mount a suppressor.


More than a dozen companies sent their offerings, and the designs ranged from the classic Heckler & Koch (HK) MP5-style to the smaller M4-type guns chambered in 9mm.


10 Contenders


The U.S. Army awarded approximately $200,000 to 10 companies for evaluation weapons under the SCW program. Then a few weeks later, the service branch expanded the scope of the test and added three more submachine guns to the mix: the Angstadt Arms’ UDP-9, the HK UMP9 and the Noveske Sub Compact Weapon.


The companies awarded contracts were from the U.S. and Europe:

  • Angstadt Arms for UDP-9
  • Beretta USA for PMX SCW
  • Colt’s Manufacturing Company LLC for CM9MM-9H-M5A, Colt Modular 9mm SCW
  • CMMG, Inc. for Ultra PDW SCW
  • CZ-USA for Scorpion EVO 3 A1 submachine gun
  • HK for UMP9
  • Lewis Machine & Tool Company for MARS-L9 SCW
  • Noveske for SCW
  • Quarter Circle 10 LLC 5.5 CLT and 5.5 QV5 SCWs
  • SIG SAUER Inc. for MPX SCW
  • Trident Rifles LLC through B&T MP9 machine gun
  • Zenith Firearms for Z-5RS, Z-5P and Z-5K SCWs.


The Weapons


Colt’s CM9MM-9H-M5A, CMMG’s Ultra PDW, LMT’s MARS-L9 SCW and Quarter Circle’s 5.5 CLT and 5.5 QV5 SCWs are based on so-called short-barrel AR-15 “pistols” using the AR-15/M16/M4 operating system, which could be an advantage compared to the others that are HK MP-5 submachine gun functioning. The U.S. Army has a handful of MP5 submachine guns in its inventory already. The others such as the SIG SAUER MPX, CZ Scorpion and MP9 are unique designs.


RFI Halt and the New Notice from Command

Then, in July, it appeared the program halted when the RFI was canceled after 13 submissions were received. In a few short weeks, a Notice was posted, modifying some of the requirements.


On July 26, 2018, the U.S. Army Contracting Command again was seeking proposals in regards to a Prototype Opportunity Notice SCW (PON) with the purpose to award up to six prototypes with the goal of delivering a quantity of 15 functional weapons. The ultimate objective of this program was to acquire a highly concealable SCW system capable of engaging threatening personnel with a high volume of lethal force while accurately firing at close range with minimal collateral damage. According to the PON for SCW, issued by the Army Contracting Command, “United States military operations take place worldwide and in all types of terrains as well as under every environmental condition. The Secretary of the Army and/or the Chief of Staff approves senior commanders and key personnel as High Risk Personnel (HRP). HRPs are authorized a Personal Security Detail (PSD), which are assigned to guard against outlined threats. To address this operational need, PSD military personnel require weapons with greater lethality than pistols that are more concealable than rifles. The ultimate objective of this program is to acquire a highly concealable Sub Compact Weapon (SCW) system capable of engaging threat personnel with a high volume of lethal force while accurately firing at close range with minimal collateral damage.”


The SCW system for this prototype OTA has the following Go/No-Go requirements and desired goals through the prototype testing phase as outlined in the following Attachment 2—SCW Test Plan Outline:


Capability Go/No-Go Requirements

Compatibility—Capable of attaching accessories/enablers.

Ammunition—9mm (9x19mm North Atlantic Treaty Organization (NATO) and qualified Sporting Arms and Ammunition Manufacturers’ Institute (SAAMI) commercial ammunition). Must perform optimally with 147 grain 9mm ammunition. Must be able to fire marking/training round.

Firing Mode—Semi- and full-automatic selectable.

Ambidextrous Controls—All controls on both sides of weapon.

Safety—External safety control that prohibits firing.

Magazine Capacity—Shall include 20-round and 30-round magazines.

Magazine Loading—Magazines shall load from the bottom of the weapon and forward from the trigger.

Weapon Color—Entire exterior surface of the weapon system to include all components shall be non-reflective black.

Weapon Length Without Suppressor—Weapon shall be less than 15 inches overall in collapsed position.

Weight—Weapon Only, Unloaded with Slings—Weapon shall be less than 7 pounds.

Buttstock—Telescopically collapsible.

Barrel Length Without Suppressor—Shall be no longer than 5.5 inches.


According to the above requirements, the Sub Compact Weapon shall be a small and concealable 9mm. The buttstock shall be telescopically collapsible, not foldable. The SCW system for this prototype OTA has other desired goals which are part of the prototype testing as these factors: Rough Handling, Accuracy/Dispersion, Acoustic, Rate of Fire, Reliability, High Temperature, Low Temperature, Recoil, Toxic Fumes and User Evaluation—Soldier Touchpoint (Weapon Comfort, Controllability, Concealability, Maintainability, Recoil, Trigger, Ease of Magazine Change, Sight-Ability and Access to Controls during a series of operationally realistic engagements).


U.S. Army Selects 6 Companies for Sub Compact Weapon Prototype Opportunity

Posted September 24, 2018, U.S. Army Contracting Command, on behalf of Project Manager Soldier Weapons, announced it has awarded contracts to the following companies to provide 9mm Sub Compact Weapon prototypes: Angstadt Arms, B&T USA, Global Ordnance, Shield Arms, SIG SAUER and Trident Rifles (Trident Rifles submits weapon from Swiss B&T AG along with B&T USA).


Details on specific models/specifications have not been made public due to confidentiality. Global Ordnance currently offers also a semiautomatic pistol version for the U.S. Commercial market and so do the other companies mentioned here.



9x19mm SCW-9 Submachine Gun, Angstadt Arms

The Angstadt Arms SCW-9 Sub-Compact Weapon.

The SCW-9 is designed to meet the strict requirements of the U.S. Army Sub Compact Weapon Program. When the last round is fired, the bolt is held open. The lower and upper receivers are made of 7075-T6 billet aluminum. The size and weight allows the gun to be ultra-concealable. The single rail on the SCW stock is positioned alongside the upper receiver. This provides added clearance above the safety selector switch resulting in faster manipulation and safer use.



  • Semi-firing mode (data here for pistol version).
  • Rear charger, ambidextrous safety/fire mode selector
  • 20- and 30-round magazines.
  • The magwell is flared for faster reloads and GLOCK 9mm magazines can be used.
  • Non-reflective black color.
  • The overall weapon length is 14.7 inches collapsed.
  • Weight 4 pounds—weapon only, unloaded with slings.
  • The buttstock can be opened without pressing a button by just grabbing the stock and pulling back. The collapsed stock length is 2.5 inches.
  • The 4-inch barrel length without suppressor has a 3-lug adapter for sound suppression.



Stribog AP9 A3S from Global Ordnance.

9x19mm Stribog AP9 A3S, Global Ordnance


All fire controls except the charging handle are in the same location as an M4. The Stribog uses a forward non-reciprocating charging handle. This allows the (operator) to maintain sight picture with the firing hand on the pistol grip when charging the weapon. It has a lower and upper Picatinny rail.



  • Semi- and full-auto firing mode.
  • All controls are fully ambidextrous.
  • Three position safety, safe, single-shot, full-auto firing mode.
  • 20- and 30-round magazines.
  • Magazine loads in front of trigger housing.
  • Black weapon color.
  • Weapon length without suppressor: 13 1/8 inches.
  • Weight 5.63 pounds—weapon only, unloaded with sling.
  • Telescoping steel buttstock, locks in open and closed position.
  • 4 5/8-inch barrel length without suppressor.

Source: Global Ordnance

SA-9, Shield Arms’ AR-style 9mm sub gun.

9x19mm SA-9, Shield Arms

SA-9 is a closed-bolt, blowback-operated AR-15-style submachine gun compatible to GLOCK.



  • Safe, semi and full-auto firing mode.
  • Ambidextrous controls.
  • Manual safety.
  • 20- and 30-round magazines.
  • Magazine loads in front of trigger housing.
  • Non-reflective black color, per the SCW requirements.
  • Weight 5.5 pounds–weapon only, unloaded with sling.
  • Barrel length 5.5 inches without suppressor.

Source: Shield Arms

SIG SAUER MPX K, from top, no. 2 SIG MPX K and no. 3 SIG MPX K with SD9 suppressor. Both with pivoting contour brace and SIG SAUER ROMEO4T closed red dot sight.


The operating system is a short-stroke gas piston system with fully closed and locked rotating bolt system, which provides maximum safety in case of bullet or water obstruction in the bore. It has operator lever changeover and stock configuration (5-position telescopic or folding). With AR-style ambidextrous controls and a rear charging handle that does not interfere with rail-mounted accessories, it will be familiar to the soldiers. The top rail is full-length, and the barrel is suppressor-ready.



  • Select fire (safe, semi, full-auto).
  • AR-style ambidextrous selector and magazine release.
  • 30-round capacity.
  • 114mm/4.5-inch barrel.
  • Aluminum M-LOK handguard.
  • Telescoping/folding 5-position stock.
  • Barrel length 4.5 inches.

Source:, 2018 catalogue

B&T APC9 SMG, Trident Rifles.

9x19mm APC9 (B&T), Trident Rifles

The APC9’s operating system is a closed-bolt blowback system. The APC9 is first choice, not only for normal police duty but also for SWAT units. The APC9’s primary sighting system is the Aimpoint Micro TL on a Picatinny rail. The upper receiver has integrated flip-up backup sights.



  • Semi- and full-automatic firing mode, rate of fire 1,080 rounds.
  • Ambidextrous safety/fire mode selector. Interchangeable charging handle.
  • 15-, 20-, 25- and 30-round magazines.
  • Magazine loads from the bottom of the weapon and forward from the trigger.
  • Non-reflective black color.
  • Weapon Length 15 inches overall in collapsed position without suppressor.
  • Weapon weight 6 pounds (including Aimpoint and 30-round magazine).
  • Telescopic buttstock; also available are foldable, folding and helmet stock for visored officers.
  • 7-inch barrel length without suppressor.

Source: B&T Webshop at

APC9 PRO K. It felt as a light and compact weapon. Around 60% of the components are made of polymer materials. Shown with two types of suppressors and Aimpoint Pro optics. The magazines have a transparent part so it’s easy to see remaining rounds. It has a collapsing stock, dual folding, non-reciprocating charging handles and M-Lok slots on the handguard to accept aiming and illumination tools. B&T also gave it a threaded barrel with a tri-lug thread protector in order to maximize compatibility with existing suppressors. This model is adapted to strip rounds from not only B&T sub gun mags but also with GLOCK and SIG SAUER P320 pistol magazines.

The Winning Sub Gun


On March 29, 2019, the U.S Army chose B&T USA’s APC9K for its New Sub Compact Weapon. The Sub Compact Weapon Production-Other Transaction Agreement (P-OTA) is awarded based upon successful completion of the prototype project proposed by B&T USA in response to Sub Compact Weapon (SCW) Prototype Opportunity Notice: W15QKN-18-R-032M, evaluation of testing results and subsequent updated proposal request letter for Follow-on Production Award. The purpose of the P-OTA is to purchase 350 SCWs ($2.5 million), with an option for additional quantities of up to 1,000 SCWs, with slings, manuals, accessories and spare parts to replace the MP5. Beyond what information the Army already has released, B&T USA told this author that they could not tell what exact configuration the weapon has, due to restriction of the contract rules. That’s understandable due to confidentiality.

The APC9K is the next leap in the evolution of the already-proven APC9 Family. With the ambidextrous, non-reciprocating charging handles and its other advanced features, one can conclude that the APC9K has satisfied the Go/No-Go requirements and desired goals through the prototype testing phase as a highly concealable Sub Compact Weapon system.