In this Instructable I'm going to show you how to mod a Nerf Nitron into a semi-automatic gun. You might ask yourself, who in their right mind would turn a fully automatic gun into a half automatic one? The answer is simple, it gives you better control, is lighter and who has ever fired a Nerf Nitron knows how ridiculously slow it normally is. This combined with a voltage mod makes this gun simply amazing (now it takes about 5 seconds to fire 20 shots).

This mod is not for beginners, don't proceed unless you are certain, that you are able to do it.

	before (9V)	after the mod (14.8V)
Weight [g]	1577	789
Length [cm]	65.5	41.5
Time to empty 20 shot magazine [s]	12	5-6

It also shoots a lot further, but I don't have the possibility to compare them at the moment.

Step 1:

What you need:
• Nerf Nitron
• Modeling clay (e.g. Apoxie Sculpt or Milliput)
• Body filler (optional, e.g. Bondo)
• Tension spring
• M3 screw 20 mm long
• sanding paper
• Strong, two component glue
• 4 X AAA battery holder case (3 x 3.7V batteries and one 1.5V)
• Primer, paint, clear coat
• Silicone Spray Lubricant

Tools:
• Hot glue gun
• Strong two component glue
• Soldering iron, solder
• Phillips screwdriver
• Pliers
• Fretsaw or scroll saw
• Drill (3 mm drill bit)
• Diamond file

Step 2: Take It Apart

Carefully take the gun apart. Then remove all the parts, that I highlighted in the first photo above (most of them are security features, that we won't be needing any more), as well as the motor in the back. Afterwards remove the rails behind the trigger, so that it can be moved all the way back, as shown in the second picture.

Unsolder the wires of the battery compartment, but don't get rid of it, we will be needing it later.
Next you will have to remove rthree pins from the back (in my opinion the best way to do this by using pliers and carefully moving the pin from side to side until it breaks off) and glue them to different parts of the gun as shown in the pictures. I was struggeling a bit with the pin shown in the fourth picture. I ended up using a diamond file to loosen it.

I've summarised everything I've done in this step in the video, to give you a better understanding:

Step 3: Sawing

Now to the fun part. The first and second picture of this step show you where you will have to saw the stock off. I also removed the handle in the front, because in my opinion it didn't fit with the shorter gun.

Next you will have to saw the the part that connects the trigger to the shooting mechanism of the gun (I've uploaded the inkscape file here). As you can see in the pictures, I used the plastic from the battery compartment to do so.

Mark how far the sliding mechanism goes back (as shown in the fifth picture), drill a hole, put a 20 mm M3 screw trough it and connect it to the green pin with a spring (There is a picture in step 5). I also shortened the rail and glued a part of it behind the sliding mechanism to prevent it from sliding to far back.
Make sure, that the distance is right, else the vortex disk will get stuck.

Step 4:

This part is a bit annoying, because you will have to sand quite a lot. I started by filling the bottom with Apoxie Sculpt.

Then you will have to remove the rails to make sure, that the battery compartment fits. It probably would have been a lot easier, if I had left a bit more of the gun in the back, so that the battery compartment would have fitted entirely it to it, but I'm happy how it turned out in the end because it looks smoother.

I covered the battery holder in saran wrap and tape on one side, to make sure, that it could be taken apart later. Then I filled the holes with body filler. After letting it set I sanded the pieces, applied an other layer and sanded again.

Step 5: Final Touches

At this point I was really frustrated, because pulling the trigger was pretty hard due to the disks sticking together. So after setting this project aside for a few months I decided to give it an other go by using silicone lube (on the gun and the disks). To my surprise it worked as a charm, hardly any force is needed any more, to pull the trigger (else I probably would have used a linear bearing, but it was really not necessary any more).

As finishing touches I used hot glue to prevent the wires from moving around and a piece of orange scrap plastic to prevent the connector piece from sliding over the screw (You can see how it is attached in the second picture). I also added a bit of sugru to reduce the noise of the mechanism sliding back.
Next I used quite a lot of hot glue, to prevent the safety mechanism that was on top from moving (I guess I could have gotten rid of it, but this seemed like the easier way out).

Step 6: Painting Time

Yay, painting ;-)... But before we get there you should sand all the pieces, because it will help the paint to stick better. Then use a plastic primer. Remember to use thin layers, you don't want to ruin your gun at this point with a bad paint job.
After painting the gun, I dry brushed it to give it more of a used look.

Now all you'll have to do is to put everything back together and enjoy your powerful, neat looking new gun.