A Visit with Vltor - Part 4 - The "Mod O's" and M32


Back to Part 3

Much of my attention that day was spent on these weapons - the FN Mk46 Mod 0 and Mk48 Mod 0. Both weapons have an aura of mystique that the standard M249 doesn't, mainly because they were developed for SOCOM (Special Operations Command) to meet the needs of Special Operations Forces, most visibly the U.S. Navy SEALs. Truly the definitive 'exotic' weapons. Actually, my first encounter with these weapons was at the SEAL compound in Coronado, where I took these photos. But while I got a chance to examine and handle them, I didn't get to shoot them. I really digged the lightweight and compact Mk46, so when Eric told me that Vltor had bought both weapons, I was very excited to get the chance to shoot them to my heart's content.

M249, Mk48, Mk46

Mk48 and Mk46

Mk48 (top), and Mk46

Belts on the feed trays

Mk 46 Mod 0

The Mk46 Mod 0 is based on the M249 family of weapons (about 80% parts commonality with the M249), with modifications to make it more compact and lighter than the standard SAW, while retaining the reliability and functionality of the full size weapon. I don't know what it is, but just making a shorter version of just about any weapon makes it look helluva lot cooler, and the Mk46 is a prime example. It's similar to the FN MINIMI SPW (Special Purpose Weapon) which added Picatinny rails to the M249 Para SAW and did away with the magazine feed to make it lighter. The Mk46 added a top rail to the handguard and can be had with either the fixed or Para stocks. The Mk46 also has a special finned 16" barrel for improved cooling and light weight and also does away with the vehicle mounting lug and carry handle. Like the M249, it's a belt fed 5.56x45mm NATO gas operated, air cooled machine gun. The titanium bipod is removable by removing and replacing the gas tube under the barrel. Instead of the nice parkerized or anodized finishes we're used to seeing on firearms, the Mk46 and 48 have what look like semi-crude paint jobs. Apparently, it's a special Teflon finish for salt water corrision resistance and reliability. The flash hider is different from the M249's and is compatible with SOPMOD suppressors.

Left view

Right view

Left side receiver markings

Right side receiver

Flash hider details

Top cover open

The 4lb reduction over the M249 is very noticeable, especially since the Mk46 has an empty weight of only 13lbs. Some M14's with all the doo-dads and sniper rifles weight nore than that. Look in the photos below - I'm a not a big guy, and with an overall length of 36", the Mk46 still looks relatively small in my hands. That should give you a good idea of the compactness of the weapon. We didn't have the ammo feed boxes that mount under the receiver to hold the belt, so I shot it with the belt hanging freely. Like the M249, the belt must be held in place while the top cover is lowered, as it doesn't have a tab than holds it in place like on the Mk48. Vltor had ordered the soft ammo belt pouches that mount under the Mk46 and 48, but they hadn't arrived at that time, so that's why I'm firing them with a loose belt hanging.

Shooting the Mk46 was a very pleasurable experience. Once I got my offhand stance figured out (I was trying to shoot it like an M4, but I learned that I had to have a bit more aggressive stance), it wasn't much different than firing an M4 in full auto. The cyclic rate is supposed to be about 725 rounds/minute which is on par with the M4 and controllable enough for short bursts. The barrel can be changed quickly by pressing the barrel lock on the left side of the receiver. There's no quick-change handle on the barrel so you've got to handle a hot barrel with gloves or just drop it on the ground to cool off. We'd swap out barrels with a spare when we felt it was needed. While the Mk46 was light enough to shoot offhand like a rifle, it's still a relatively heavy platform (compared to an M4) for the 5.56mm cartridge, which makes it very extremely controllable and just a sweet gun to shoot in the prone position. I can see why the SEALs like it for CQB and laying down suppressive fire. I ran around with it shooting from standing, kneeling and prone, and I can honestly say that I had fallen in love with this little weapon at the end of the day. It was tough to part with it.

Here's a short clip of me shooting the Mk46.


Firing offhand


Links and brass pouring out

Mk 48 Mod 0

The Mk48 Mod 0 is the 'big brother' to the Mk46, chambered for the 7.62x51mm NATO round. It was developed for Naval Special Warfare (NSW) (read: SEALs) to replace the Mk43 (M60E4) in the lightweight 7.62 machine gun role. It shares 70% parts commonality with the Mk46, and at a glance, it's sometimes tough to tell them apart unless you're familiar with the visual differences (I found the 4" longer barrel and detachable carry handle on the Mk48 to be the most obvious clue). The trigger group on the Mk48 has also been moved back a tad, relative to the receiver. Like the Mk46, the Mk48 also has five Picatinny rails (four on the handguard and one on the top cover) for compatability with SOPMOD accessories. Other differences are internal, with the Mk48 having beefed up parts for the heavier caliber. At 5 lbs heavier (18lbs) and four inches longer than the Mk46, it's most noticeable when fired offhand. It has the same lightweight bipod as the Mk46.

The Mk48 has a heavier and longer barrel than the Mk46, without the fluting/fins. It also retains the vehicle/pintle mount of the M249 (the round hole at the front of the bottom handguard rail). The swivelling carry handle is detachable by taking out a pin.

Mk48 right side

Left view

Left side details

Barrel details

Right side receiver markings

As I mentioned above, the Mk48 might look very similar visually to the Mk46, but it's a different story when you heft it. The additional 5 lbs makes its presence felt, and it just feels 'beefier' and not as compact. Obviously, to the guys who do this for a living, it IS lightweight and compact - it's all a matter of perspective. Not being one of those guys, I found it heavy to shoot offhand from the shoulder like a rifle for anything more than a few short bursts. Back in Coronado, when I first handled the Mk48, the SEAL who was showing me the weapon noticed I was left handed. He said "You're a lefty? Dude, this gun is going to beat you up!" He was right, it turned out. The links and hot empty cases are ejected with such force that I had small bruises up and down my forearm as it was directly in line with the ejection port when firing offhand. I was using my right arm to support the weapon; holding onto the vertical grip. If you look at the short clip below of me shooting the Mk48 prone, you can see that the cases don't just fall out of the ejection port - they're flung out all over the place. Shooting from prone was the way to go for me, of course, but it there was more felt recoil and it wasn't as pleasant to shoot as the M240B or PKM, due to its lighter weight than the 240 and higher rate of fire than the PKM. But with it's relatively short length and light weight, as far as a 7.62mm machine gun goes, it's easy to see that in the right hands, it'd be a devastating weapon.
FN Herstal recently introduced a 7.62mm version of the MINIMI, to fullfill the Light Machine Gun role that would give the soldier more power than the 5.56mm MINIMI in a lighter weapon than the MAG (M240). Go to FN Herstals home page for more information.

Here's a clip of me shooting a short burst through the Mk48 in the prone position. 


Recommended reading: Link 1, Link 2

Top cover open

Removing handle

Milkor M32 MGL (Multiple Grenade Launcher)

The South African company Milkor is a name synonymous with single and multiple-shot grenade launchers. Milkor USA, Inc. which is owned by Abrams Airborne Manufacturing, produces the MGL for the U.S. and NATO market, and is now co-located at the Abrams manufacturing plant along with Vltor. The basic MGL design is made in other countries under license, but the version seen here, adopted as the M32 MGL by the USMC, is unique to Milkor USA, Inc. It's a semi-automatic, rotating cylinder, six-shot 40mm grenade launcher that can be used with lethal and non-lethal 40mm ammunition. It has a minimum range of 30m and maximum of 375m. The barrel has progressive rifling, meaning the twist rate increases as the round travels down the barrrel. The frame is constructed of stainless steel, and the cylinder is machined from 7075-T6 aluminum. The Vltor design influence is obvious in the handguard, with four 1913 rails around it, and the Vltor modstock and butt pad, which come standard on the M32. The TangoDown vertical grip is also standard on the M32. Finish is either black or Flat Dark Earth Gunkote.

The large rotating cylinder hold six 40mm rounds with a maximum length of 140mm. A reflex sight mounted on top enables range estimation and impat adjustment. Once the range is determined, the sight is rotated up or down and set to the correct detent, which are marked out to 375m. The sight is battery operated by a single AAA battery which provides 500 hours of operation. Rather than swinging out of the frame like a revolver, the rear part of the frame to which the pistol grip and buttstock are attached rotates to allow access to the cylinder.

MILKOR at Abrams

M32 right side

Left side

Rear frame rotated


With the rear swung to the side and the safety on, the cylinder is first wound up by rotating it counter-clockwise against spring tension. There is a spring which rotates the cylinder clockwise, while the clockwise travel is stopped by a locking mechanism when each chamber is lined up with the barrel. 40mm rounds are then loaded into the chambers. The rear half is swung closed and the M32 is ready to rock and roll. The M32 has a double action trigger - it fires just like a double action revolver. However, unlike a revolver, which depends on the cycling of the trigger to advance the cylinder, the M32 depends on a round being fired to advance the cylinder to the next chamber. The is a cylinder locking mechanism that bleeds off gas from a hole in the barrel when a round if fired. The gas pushes up on a piston, disengaging the cylinder lock, allowing the cylinder to rotate under the coil spring tension. In case of a hangfire, where detonation of the primer is delayed, this acts as a safety feature by not allowing the cylinder to rotate until the round goes off. If the cylinder advanced automatically with each pull of the trigger, regardless of whether a round has been fired, it'd be possible for a hangfire round to be rotated away from the barrel, and blow the receiver up if it goes off. The operator can also choose to manually advance the cylinder, and select a certain chamber if different types of ammunition has been loaded into the numbered chambers.

The angle of the buttstock can be adjusted to two positions. Either way, it's going to be more 'chin weld' than cheek weld as the range increases, and the elevation angle of the barrel/weapon increases. Length of pull adjustment is identical to the M4. Loading and operation of the M32 was simple enough - it just takes practice to swing it out, wind it up, load it and close it. After the rounds are fired, the empty cases are ejected in the same way as a revolver, by pushing a plunger on the front of the cylinder. Eric Solberg from Milkor, who's put thousands of 40mm rounds downrange doing demos was kind enough to show me the basics. I shot some practice rounds downrange, checking my hits after each one. The M32 kicked just like the M203 - more of a slight shove than a sharp kick. In the clip below, Eric demonstrates the right way to shoot the M32 (after I pop off one round), with his elbow down and shoulder forward, and puts out all six rounds in less than 3 seconds, then unloads the weapon. He makes it looks easy; and with practice, it probably is. Helluva lot of fun. One Marine could do a lot of damage to the enemy. Even more if he has one of these.

M32 Clip


Part 5 - The Garwood Industries M-134G 7.62mm Minigun

The fellows from Garwood Industries, Tracy Garwood and Randy Myer brought out their M-134G 7.62mm Minigun to join in the shoot. This was something I was VERY excited about, never having fired a minigun. Garwood Industries sells M-134G newly manufactured parts and subassemblies to upgrade and modernize existing military miniguns. All components are manufactured by their manufacturing partner, using state of the art tooling and machinery.

The 7.62mm minigun/Gatling gun as originally developed by General Electric is a six barrel, electrically driven, belt-fed machine gun firing at 3000-4000 rounds per minute. It weighs approximately 61 lbs. There's a ton of information to be found on the M-134 minigun, so I won't parrot it here. A good start is Monty's Miniguns page.

Although miniguns have been used in a bunch of movies, many gun enthusiasts of my age will remember 'Old Painless' in the movie 'Predator' - the minigun carried by Jesse Ventura's character, as probably the first time we'd seen a minigun featured like that. And boy, was it cool. Unfortunately, portable, hand-held 7.62mm miniguns only exist in the fantasy movie world, as the weight and recoil of a minigun firing real ammunition prevents it from being a reality. In addition to the gun itself, the minigun needs an electrical power source to run, a solid mount, and a supply of ammunition. The peak recoil generated at 4000 RPM is 375 lbs, with the average at 250 lbs.

The Garwood M-134G was mounted on a pintle mount with their vertical support arm and yoke, securely weighted to the ground with sandbags. I don't recall the capacity of the ammunition magazine, but it was about 3000 rounds of linked 7.62mm ammunition. The feed chute ran from the ammunition magazine to the feeder/delinker. Some of the parts on the Garwood were proprietary at this time, so certain components have been blacked out in the photos below. I had a lot more photos of the minigun itself, but can't show them, at the request of Garwood. The Garwood minigun also had their toke with sight rail, on which a Eotech sight was mounted on, and a PEQ-2 laser aimer off to the side for night shooting with NVGs. The minigun had spade grips, which are gripped firmly while pressing either trigger button on the gun control unit to fire the weapon. The on/off switch was housed inder the red switch cover, which had to be flipped on before the gun would go 'hot'. After firing, the cover is flipped down to cut power to the minigun and safe it. There was an extra button at the lower left of the gun control unit that activates a booster unit. There wasn't one installed at this time, but a booster unit mounts on top of the ammunition magazine and pushes the ammunition through the feed chute up towards the gun. This results in a 1000 RPM increase, to 4000 RPM.

M-134G on pintle mount

Spade grips and gun control unit

Business end

Feed chute

Tracy and Randy took the time to explain the operation of the minigun and its major components, and also what to expect when firing the weapon. I watched Tracy fire off a few bursts, and standing to the side (and as close as was safe), I could feel a pressure wave hit me when the gun went off like a buzz saw. Most of us have been beside a rifle being fired, and have experienced the muzzle blast and concussion. .223 is annoyingly sharp, and .308 you can definitely feel. Now multiply that into an almost continuous blast of 50 rounds per second, and that's what standing next to a minigun feels like. I loved it. Another interesting thing to look at is the steady stream of empty cases and disintegrated links streaming out of the weapon. The cases are ejected from the left and links from the bottom right.

Now it was my turn. As Tracy explained, when the trigger is pressed, the initial recoil pushes back on the mount, flexing the post. As a result, the muzzle(s) dip down slightly for a second. Knowing that, I aimed slightly high in anticipation of the dip. It's funny, when the minigun fires, EVERYONE stops what they're doing to watch. I fired a few short bursts (trying to be nice and conserve ammo, like I always do when shooting someone else's). Randy said 'Fire longer bursts - give the gun a second to settle'. I was more than happy to oblige. I fired off longer bursts, and the gun did indeed 'settle' once you went past the inital recoil dip. Then, it required barely any effort to keep it on target or move it to the next one. It's hard to describe how rewarding it is to watch the impact of the rounds kicking up clouds of sand and dust. There's a very short split second delay from when the trigger button is depressed and the first rounds are fired, which is the gun loading the first rounds as all chambers are empty. There's also a second after the trigger is released that the barrels keep spinning. This is to ensure that the barrels are cleared of live rounds after the trigger is released, so no live rounds remain in the chambers to cook off.

It was just an amazing experience - the ultimate small arm I'll probably ever get to fire. Thanks to Garwood Industries for bringing it out and letting me have a go.

Firing the M134G Clip




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