FAB Defense K.P.O.S. Glock Pistol to PDW Conversion
By Todd Burgreen

Many consider Glock the standard by which fighting pistols are held based on capacity, weight/firepower ratio, ruggedness, and reliability. A new product from FAB Defense in Israel and currently distributed in the U.S. by the Mako Group seeks to capitalize on these positive traits with the KPOS Glock-to-rifle conversion stock. The KPOS aluminum stock chassis transforms a Glock handgun into a viable personal defense weapon (PDW) category.

The KPOS was designed with personal security details and covert operations in mind, especially if the Glock 18 machine pistol is utilized. The KPOS arrives with Picatinny style rails along the top, sides, and bottom allowing for performance enhancing accessories such as vertical forward grip, optic/red dot sight, flashlight, or laser aiming device to be mounted. The aluminum framed KPOS stock features a side folding stock that further reduces the weapon's footprint when folded. The KPOS measures 13.5 inches with stock folded and 21.5 inches with stock deployed and weighs less than 4 pounds with a Glock 17 mounted. For comparison, a Glock 17 installed in the KPOS is smaller and lighter than a mini-Uzi. The KPOS unit tested works with Glock 17 and Glock 19 compatibles (G17, G18, G34, G22, G35, G19, and G23). Other KPOS models for SIG Sauer and Springfield handguns are expected.

In the U.S., the KPOS converts your Glock pistol into a Short Barreled Rifle (SBR) classification and must be treated as such with an approved Form 1 from the BATFE before you possess this stock and install a weapon in the KPOS. Failing to do so is a violation of Federal law with extremely serious consequences that may result in fines and/or imprisonment.

The KPOS stock arrives in a hard case that includes folding forward vertical grip, modified Glock slide back plate for charging handle adaptation, and detachable single point sling. The patented KPOS design locks both the front and back of the Glock into the KPOS frame without requiring any tools. The Glock's railed dust cover is used as an attachment point in the front and a simple wedge block in the rear secures the frame. This prevents the pistol from moving ensuring reliability and stable point of aim. The Glock's back plate located at the slide's rear is switched out with a modified version enabling a charging handle to project out the KPOS's left side for slide manipulation when installed in the KPOS. The Glock's open sights are still accessible, though mounting a red dot or other type of optic is best for extending effective range.

Many will question the utility of employing a pistol cartridge in a shoulder fired weapon. Most engagements happen within a 100 yard range, especially in a civilian setting, with handling and reliability playing more of a factor in quick, reactive engagements than specific caliber used. Less experienced shooters will find the lower recoil pulse and muzzle blast of a pistol caliber fired from the shoulder easier to manage, which often times will translate into better accuracy.

A Glock handgun is transformed into a much more potent package when mated to the KPOS stock. A Glock17 using a Lone Wolf Distributors stainless barrel with threaded muzzle was mounted in the KPOS for this review. One note of importance here that once registered as an SBR, a weapon used with the KPOS is required to stay in this configuration and should not be used in other applications. The KPOS allows the mounting of a suppressor if a user desires. The barrel shroud is easily removed allowing for a suppressor's diameter. The advantage derived from the Glock KPOS SBR is that effective range and shootability is increased compared to a handgun; thus the PDW reference at the beginning of the article. This is based on the KPOS's multiple points of contact when interfaced with the shooter. This consists of shoulder, cheek, and hands spread further apart for more stability compared to when handling a handgun.

The KPOS's rail system maximizes potential with accessories such as an optics, lights, lasers and vertical forward grip. The vertical foregrip has fast become a standard accessory on any rifle or carbine equipped with a forward accessory rail. The increased leverage and control offered by the vertical foregrip aids in weapon manipulation and stability when firing. An Aimpoint H1 and Insight Technology M6x Tactical Laser Illuminator were added to the KPOS's rails.

The Glock 17 used in conjunction with the KPOS conversion was a proven performer with upwards of 4,000+ rounds fired without issue. Importantly, the Glock maintained its reliability once installed in the KPOS. Installation is accomplished by first turning the KPOS upside down. Towards the back of the stock located near the folding stock hinge point is a pin. Remove this. This allows you to next slide the metal retaining plate out the back. After this, insert the Glock all the way towards the front where there is an interface between the Glock's dust cover and the KPOS that locks the front of the Glock down. Make sure the Glock's front dust cover side rails slide into the KPOS unit before turning the locking mechanism located on the side towards the fully engaging the dust cover's cross slot. If done correctly, the GLOCK should not be able to move at this point. Slide the metal wedge plate up against the Glock's rear frame and reinsert the pin.

A wide range of 9mm loads were tested including 115gr, 124gr, and 147gr JHP and FMJ loads from Black Hills, CCI, Federal, Hornady, Remington, Winchester, and Wolf. The Glock KPOS SBR was sighted in 1 inch high at 25 yards, which gives an approximate 50 yard zero and 7 inches low at 100 yards trajectory depending on exact ammunition used. This is a flatter trajectory than most would expect. The decision to utilize the threaded Lone Wolf barrel is a nod to future plans to incorporate a suppressor with the Glock KPOS SBR as 147gr 9mm is an obvious choice for use with a suppressor. Range evaluation consisted of a mixture of drills establishing durability, reliability and handling. Firing behind cover, engaging multiple targets, magazine changes, targets at CQB distances to 100 yards, and off-shoulder shooting made up the bulk of these drills. Rounds fired during T&E quickly rose to over 800 with only a few range visits as it was too tempting to keep feeding in the Glock magazines. No failures were experienced no matter how quickly or how many 33-round Glock magazines were fired. This is a credit to both Glock and the KPOS chassis being well designed as to not interfere with the mounted weapon's functioning. Purposely induced malfunctions were cleared in the same manner as one is accustomed to with a Glock thanks to the side charging handle and operating controls not being compromised with the KPOS stock chassis. A large portion of the Glock slide and ejection portion is not obscured, which further assists in no reliability issues.

The compact size of the Glock KPOS SBR cannot be overstated. A DeSantis DSD shoulder holster rig was tested as one carry method. It is not being represented that the KPOS SBR is a substitute concealed carry weapon in lieu of inside the waistband carry. However, the DSD rig proved a viable carry method under certain conditions. The KPOS chassis with stock folded is smaller than a mini-Uzi and rides under the user's right arm with multiple 33-round magazines carried under the left arm. Many would favor discrete off body carry of the KPOS SBR in a back pack or attaché/briefcase with another 9mm Glock handgun carried concealed thus offering advantage of same caliber/magazine interchangeability. The availability of proven Glock factory 33-round 9mm magazines is huge advantage for the Glock KPOS platform. The increased capacity represented by the 33-round magazines should not be underestimated compared to other non-9mm calibers within Glock family, not to mention other manufactures as a whole. The KPOS's folding stock is quick to deploy and sturdy once unfolded in the shooting position. The two-handed grip afforded by the KPOS's vertical forward grip combined with Aimpoint H1 red dot sight picture is more than adequate reacting to a situation until the stock can be deployed.

In an effort to determine the advantage of mounting a Glock in the KPOS, the Glock that was installed in the KPOS was fired in its pistol configuration at 15, 25 and 50 yards at a plate rack featuring multiple 6-inch round targets. This was an effort to establish a baseline of field accuracy with shooting done standing unsupported. The Glock was then installed in the KPOS and fired in the same format. The accuracy and increased time differential in falling the plates definitely supports the advantages offered with the incorporation of the Aimpoint H1 red dot sight and ability to shoulder the weapon. While plates were successfully engaged at 15 and 25 yards with relatively few misses with the Glock in its original form, 50 yards was challenging with results less than satisfying. The KPOS Glock SBR proved much faster at 15 and 25 yards with 50 yards hits routine thanks to the shoulder stock and red dot sight. The Aimpoint H1 red dot sight assisted in engaging targets at close distances with the red dot easy to pick up rapidly, while at the same time increasing accuracy out to a hundred yards far beyond normal open sight capabilities. Handguns can engage targets at ranges much further than most realize, but this is not the norm and often under pristine conditions with plenty of time to set up. The Glock's consistent trigger pull, controllable light recoil, firing from a closed bolt, and minimal muzzle blast, further accentuates this accuracy advantage. The muzzle blast differential between a 9mm carbine versus obnoxious rifle muzzle signature is further accentuated in confined spaces such as inside a home if serving in a personal defense role. The old standard touting the advantage of having both a carbine and handgun chambered in the same caliber should not be casually dismissed, especially if an organized logistics chain cannot be counted on. The Glock 19 handgun resting in the holster on your hip can also utilize the 17 or 33-round magazines used with the Glock 17 in the KPOS slung around your neck or resting under your arm in the DeSantis DSD shoulder rig.

Of late, it seems more Glock carbine options are appearing in the market. Few offer the total package of the Mako KPOS in terms of metal manufacturing, folding stock, ease of install/conversion, and Picatinny style rails allowing for easy adaptation of accessories. A pistol caliber carbine can never be compared across the board to a weapon firing a rifle round due to effective range and lethality of the pistol round versus a rifle cartridge. However, a 9mm carbine typified by a KPOS Glock SBR is not a weapon to be ignored. Beyond a doubt the KPOS Glock is much more potent than any handgun due to its increased effective range and shootability thanks to the ability to be fired from the shoulder. The ability to keep a PDW configured like the Glock KPOS will outweigh its limitations in many people's minds. The KPOS converted Glock is substantially smaller than several other SBR rifles it was compared to consisting of AKSU-74 Krinkov/Suchka, 9mm AR, and SIG556. The KPOS Glock conversion's portability to effective firepower ratio will trump a rifle's power for many. The KPOS enhances the Glock handgun into a PDW with effective range over 100 yards via shoulder stability and sight enhancement options with the Picatinny style rails. The KPOS chassis seamlessly integrates the Glock. There is no compromise in handling or reliability with mating the Glock to the KPOS. A user has a just as positive feel with the KPOS conversion as one would with a dedicated PDW or SMG. A survey of the existing market will demonstrate few other matching weapon system options in terms of size, reliability, and capability as the Glock KPOS SBR, especially for the civilian consumer.

Sites of Interest

Mako Group
1 Lenox Ave
Farmingdale, NY 11735
(866) 753-9444

Aimpoint, Inc
14103 Mariah Court
Chantilly, VA 20151

DeSantis Holster and Leather Goods
431 Bayview Ave.
Amityville, NY 11701
(800) 424-1236

6000 Highlands Pkwy
Smyrna, GA 30082
(770) 432-1202

Insight Technology
9 Akira Way
Londonderry, NH 03053
(866) 509-2040

Lone Wolf Distributing
57 Shepard Rd.
PO Box 3549
Oldtown, ID 83822
(208) 437-0612

This article first appeared in Small Arms Review V14N5 (February 2011)
and was posted online on November 1, 2011


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