VFC MP5 Fusion Engine Conversion

IMG_0720Here are some pictures of a Polarstar Fusion Engine installed into a VFC MP5. This version of the MP5 has the extra 3 round burst mode, but since the FE doesn’t currently support the extra fire mode, the conversion locks out the extra fire select position.

The main issues that have to be addressed are the selector plate, the trigger and the routing of the wire harness to the front. The selector plate is slotted so the cog on the fire select switch can move the plate back and forth. The fire select cog is rotated 180 degrees so it is now at the top to reach the plate. There are two screws added to the body which prevent the fire select switch from over rotating in either direction.

The trigger needs to be moved from the stock gearbox to the Fusion Engine. Unfortunately the tail on the trigger doesn’t reach the hard stop in the FE lower assembly, so a screw was added to fill the gap. It is important that the trigger have a hard stop to prevent over travel from the trigger lever which can damage the Fusion Engine trigger microswitch.

The last issue is running the wire harness to the fore grip area (if you choose to put the FCU and battery in the front). There is very little room in the gun for the wiring, so the hopup block needs to be removed and milled/dremeled out to make clearance for the wire harness connector to pass through.

The Fusion Engine nozzle length (measured at 42.25mm) is basically the same as the M249 nozzle, but the M249 nozzle doesn’t have a chamfered nose, so a custom nozzle is needed, or the M249 nozzle can be modified to work. It’s may also work with an AK nozzle, which might be a tiny bit too long, so it may need to be cut down a little.

Happy Airsofting!

– Rudy

Viva Arms M1919 PolarStar Fusion Engine Conversion

IMG_2306The Browning M1919 is classic machine gun widely used throughout the early to mid 20th century, but it’s not so common as an airsoft gun. Although there are several airsoft models available, you don’t typically see these on the field, generally due to their size and weight. The Viva Arms M1919 is designed as an airsoft gun utilizing a V7 gearbox. McCenzie Mento sent his Viva Arms M1919 out to be converted to use a PolarStar Fusion Engine as the V7 gearbox had broken apart. Machine guns are particularly well suited for HPA conversions like the Fusion Engine since they can handle a tremendous amount of rounds with little maintenance and no worries about the gearbox or piston breaking down.

IMG_2287To fit the Fusion Engine into the M1919, a special bracket was 3D printed so it can use the same mount points as the V7 gearbox. Also the bracket was enhanced to lock the hopup in a vertical position, increasing the consistency and reliability of the gun. The hopup in the gun is proprietary to the gun. It allows the BBs to feed from the top and it uses a set screw to adjust the hopup. A custom length 42mm (overall length) Fusion Engine nozzle was needed, and the bucking was swapped out for a Maple Leaf 75 degree bucking to improve the feed and accuracy of the gun.

The existing trigger switch mechanism was used and simply wired up to the mini circuit board attached to the Fusion Engine. The FCU was mounted inside of the main body of the gun, along with the box mag motor control unit. There is also plenty of room in the gun for the battery.

IMG_2316The original box mag mechanism couldn’t provide a lot of BB feed pressure causing the BBs to be chopped in the hopup. So it was swapped out and replaced with the same MAG box mag mechanism I use in my Nerf gun conversion, and the same one used on the M2 conversion. I 3D printed a feed bed to fit the M1919 box mag and also significantly increased the capacity of the magazine.

Adding the Fusion Engine into this M1919 has brought it back to life and now it’s truly a formidable defense and support weapon. Time for McCenzie to invest in a lot of BBs!

Happy Airsofting!

– Rudy

M2 Machine Gun PolarStar Fusion Engine Conversion

IMG_2201The The M2 Machine Gun or Browning .50 Caliber Machine Gun is very large machine gun, and it’s extremely rare to see one as an airsoft gun. Tom DiQuattro wanted to have his M2 replica converted to a PolarStar Fusion Engine gun so he sent it out to see what could be done.

The M2 replica is massive. It’s almost 6′ long, and it weighs in at 36 lbs without the box mag. It was decided that real .50 cal ammo can would be used as the box mag for the gun, and with the box mag fully loaded, the weight of the gun tops 50 lbs!

IMG_2202The replica was made with a solid aluminum barrel. It was not bored out. I attempted several tries to bore the barrel using extra long drill bits, but I just managed to mangle up the barrel (lesson learned!), so I had to ship the barrel back to Tom where he had a friend with the right equipment properly bore out the barrel. The barrel is connected to the main body of the gun by large threads. This required that the hopup be able to fit through the front of the gun, so it can be inserted with the outer barrel, since a long 650mm inner barrel would be used with the gun.

IMG_2177A G&G/CA M14 hopup was used since it had a narrow profile and could fit through the front of the gun. To hold the hopup in place, and to provide a way for a BB feed tube to attach to the hopup. a 3D printed hopup block was created. The hopup block sandwiches the hopup and locks it in place, and also supports the front of the Fusion Engine. The rear of the Fusion Engine was held in place by another 3D printed bracket, which also supported the mini circuit board and MCU box mag circuit (which links the box mag to the trigger on the FCU).

The bottom of the gun was uncovered, so another 3D printed piece was created to close up the bottom of the receiver.

IMG_2168The trigger lever on the replica was simply a metal piece held in place with a pin, pushing against a spring. To have it work with the Fusion Engine, a hard stop was added to prevent the switch from hitting the buffer tube, and a micro switch was added so it would be activated when the trigger lever was pressed.

The .50 cal ammo can was modified to hold a MAG brand box mag. A large 3D printed feed bed was used to hold the box mag mechanism in place as well as feed the BBs down into the box mag. It has a giant capacity of about 19,000 bbs!

IMG_2173The M2 Fusion Engine conversion was a bit of a challenge (especially that solid barrel), but with the extensive use of 3D printed parts (the Makerbox Replicator 2X 3D printer has been a fantastic investment), it was able to be assembled in a very user friendly and maintainable way.

When hooked up to a large air source, high BB capacity, the M2 Fusion Engine gun will provide game changing firepower to any airsoft skirmish!

Happy Airsofting!

– Rudy

Here’s are some videos of the M2 assembly and disassembly procedure:


Here’s a sustained fire test video:

(more videos coming soon)

G&G GK5C PolarStar Fusion Engine Conversion

IMG_2126The G&G GK5C airsoft gun is very unique and rarely seen on the field. It is the airsoft version of the Swedish AK5C, which is an evolved version of the FN FNC.

The GK5C uses a V2 gearbox, but it has a few external modifications to support the unique dual selector plate implementation for the ambidextrous fire select levers. It also uses a rear gearbox pin that has been moved to a custom location, so an additional pin through hole is added to the GK5C gearbox.

IMG_2119Converting the GK5C to use the PolarStar Fusion Engine required a few extra modifications to support the ambi fire select levers. Part of the top selector plate guide rail on the left side of the Fusion Engine had to be milled away to make clearance for the selector plate.IMG_2121 On the right side, custom mount holes were added and the right selector plate was modified to use the new mount points.

IMG_2124The rear body pin is in a custom location, and unfortunately, this location is right where the Fusion Engine solenoids are located. So the rear body pin was omitted. Instead the holes were covered with self adhesive foam pieces. The lower receiver is molded in such a way that it holds the Fusion Engine very securely using the grip screws and the rear stock bolt, so the rear pin wasn’t really needed anyway.

The GK5C uses a split hopup like the KWA and JG guns (unfortunately) and it requires a custom length nozzle. Quite a bit of chamfering was needed on the hopup BB feed tube and upper section to make sure there was a clear pathway for the BBs to feed.

IMG_2112The gun has an interesting design that allows the front hand guard to be opened by pushing a lever on the right side. The FCU and battery can be located in this space, though it’s a relatively tight fit with the outer barrel and dummy gas tube.

Overall, though, the Fusion Engine works well in the GK5C, and with a bit of customization, the ambidextrous selector functionality can be maintained. With the PolarStar Fusion Engine, the GK5C gun can turn into a top performer on the field and set itself apart even further in a world crowded with a ARs and AKs.

Happy Airsofting!

– Rudy

Guitar PolarStar Fusion Engine Conversion

photo 1 Here’s my latest PolarStar Fusion Engine conversion. A truly unique airsoft gun. For those that are Guitar Hero fans, now you can show your strumming skills on the Airsoft Field.

photo 3The guitar has been specially modified so it uses the strum bar as the trigger, so you can do extremely fast semi-auto fire by strumming up and down. The whammy bar is used to enable full auto mode. It has an integrated box mag with a capacity of 5000 rounds (there’s a lot of space in the guitar body!)

Future upgrades will allow multiple fire modes by using the keys on the guitar neck, including multiple burst modes.

photo 2It comes with a built in sling as a bonus. So next time you are on the field and someone is rocking out, they just might be the most dominant head-banger on the field with a PolarStar Fusion Engine powered guitar!

Happy April Airsofting!

– Rudy

(I hope you have enjoyed this April Fools post…but watch this space…flights of fancy may yet turn into reality!)

Echo1 AR-57 PolarStar Fusion Engine Conversion

IMG_1827The Echo1 AR-57 is a unique gun that uses P90 magazines on a AR platform. To accomplish this, a proprietary hopup is used with the gun that requires an extremely long nozzle. The nozzle is one of the longest I’ve seen on a gun, beat only by the nozzle on the Sig556. To have the Fusion Engine work within this gun a custom hybrid nozzle had to be made extending a SCAR H nozzle with an AEG nozzle.

The mag well on the Echo1 AR-57 is not used, but it works well as a location for the FCU and the battery when stored in a dummy magazine.

IMG_1825The basic install is the same as any standard AR gun, except for the nozzle and changing the wiring to go forward so it can go into the mag well.

IMG_1826Look for this unique Fusion Engine gun at an airsoft field near you! (Ok, maybe if you know Brian in Vermont) 🙂

Happy Airsofting!

– Rudy

Keyword: ar57

Updated Nerfsoft Pictures and Videos

Just thought I’d post some new pictures and videos of the PolarStar Fusion Engine powered Nerf Stampede and Vulcan guns.

Here’s a Nerf Stampede hydro dipped with Multicam (before Fusion Engine conversion). I’ll be offering other camo patterns as well as Carbon Fiber.

Here’s Nerf Stampede with a tan painted body and barrel extension:

Painted Nerf Stampede

Painted Nerf Stampede

Painted Nerf Stampede

Painted Nerf Stampede

Here’s video of the tan Nerf Stampede in action:


Here’s the Steampunk Fusion Engine Nerf Vulcan from Team Vcious:

Here’s the Nerf Vulcan in action (before paint job):

Here’s a Fusion Engine Nerf Gun Shooting Gallery. I had a friend bring his kids over to use the airsoft PolarStar Fusion Engine Nerf guns in a makeshift shooting gallery. They had a blast! 45,000 BBs later and the box stand was completely demolished and it fell to the floor. Very few airsoft guns can keep up this firing rate for so many rounds and not skip a beat.