**** There is a newer version of this instructable that goes into greater detail, and covers additional modifications such as an improved shotgun attachment, motor and battery upgrades, and painting. Please check it out here:

https://www.instructables.com/id/Ultimate-Nerf-Dem...

I'll leave this one intact for historical purposes.

This will show you how I modified my Nerf Demolisher. I removed the mechanical and electronic locks, add replaced the manual missile launcher with a shotgun powered by an Xtreme Blastzooka air tank.

Step 1: Required Items

To perform this mod, you will need the following tools and materials.

Materials:

Nerf Demolisher blaster
Air Warriors Extreme Blastzooka
a 1 inch section of ¾" cpvc pipe
a ¾" cpvc slip fit to threaded adapter
a 12 inch section of ½" cpvc pipe
a 1" pvc slip fit coupler
a 1" slip fit to ¾" threaded pvc adapter
a ¾" to ½" cpvc elbow
a ¾" to ½" cpvc coupler
a ½" cpvc male to female elbow
1 drywall screw
1 Nerf dart tip

Tools:
small Phillips screwdriver
pvc cutter (or saw)
electrical tape
hot glue gun
pvc cement
knife
soldering iron
wire cutters
drill with counter sink bit
pliers
Dremel

Optional
spray paint

Step 2: Open the Blaster

Remove the four screws from the pump handle and then all of the other screws from the blaster. Make note of where the two long screws belong.

Once the screws have been removed, carefully open up the blaster.

Step 3: Remove the Locks - Optional

I didn't remember to take as many pictures as I wanted to here. There are two mechanical locks and two electronic locks that can be removed. This is not necessary for the missile launcher mod, but makes the blaster easier to operate. if you remove the electric locks, you will need to rewire the blaster

the locks are generally lighter in color than the other pieces.

remove the trigger lock, jam door lock and mag lock. once the switches are removed, you should have two short wires near the jam door. these run through the shell to the motors. mine were red and green. Solder the red wire to the pink wire on the rev switch. solder the green wire to the brown wire on the rev switch.

Now the rev switch will function all the time, even if the jam door is open or there is no magazine. the trigger should function well.

Step 4: Open the Blastzooka

To open the Blastzooka, you must pry of the orange ring at the end, just squeeze and pull.

Pry of the firing button bezel.

Remove all of the screws and open the shell.

remove the internals.

Step 5: Prepare the Air Tank

Cut the missile launcher barrel off, leaving about an inch. slide a 1” section of ¾" cpvc pipe over the orange barrel, then attach the ¾" threaded adapter. secure with pvc cement and tape.

remove the plunger and cut off the plunger tube, leaving enough to attach a cpvc elbow.

Step 6: Prepare the Pump Tube

Cut the missile launcher barrel and elbow off of the pump tube, leaving just a small section below the mounting screw. you will need to ream out the small hole so that it is large enough for a section of ½ cpvc pipe to fit through.

Step 7: Plunger Tube Extension

I originally designed this to use the Demolisher plunger to pump up the Blastzooka tank, however upon completing this, it was apparent that it was not going to work. The Demolisher plunger is approximately four times the surface area of the Blastzooka plunger, which makes it four times harder to pump. It was all I could do to pump it four or five times, and my children couldn't pump it at all. I ended up redesigning it so that it uses the original Blastzooka plunger which has been relocated inside the Demolisher plunger tube.

you should dry fit everything before gluing

start by attaching the the ¾" to ½" elbow to the back of the air tank. you will probably need to sand the back side flat to get it to fit in the shell.

attach a ¾" to ½" cpvc coupler to the section of pump tube you cut off of the Blastzooka. then attach the ½" cpvc elbow. this assembly should slide into the Demolisher pump tube. you may need to sand down a little bit of the elbow in order for it to line up with the home on top.

then cut a small section of ½" cpvc pipe to connect the two pieces.

trim the Blastzooka pump tube so that it sits flush with the end of the Demolisher tube

Step 8: Fit the Assembly Into the Blaster Shell

Align the tank so that the firing button is facing the left side of the blaster.

Because of the increased thickness, some of the supporting plastic will need to be carved away to allow the assembly to fit.

Optional: if you want to paint this, now would be a good time. I used charcoal vinyl dye.

Step 9: Plunger Modification

Cut the Blastzooka plunger to length. cut out a small slot on either side.

Cut the end off of the Demolisher plunger, leaving just enough to attach them together. I had to use my Dremel to cut away a few supports. slide the two pieces together. I drilled two small holes at the back of the plunger shaft to line up with the screw holes already on the orange piece and threaded in two of the screws from the Blastzooka shell.

It probably wouldn't hurt to glue these together as well.

Step 10: Add Firing Button

This was one of the most difficult parts. The black firing pin of the Blastzooka was just long enough to reach the side of the shell, which makes it difficult to fire. in order to make this easier, drill a small hole in the shell where the button is. I used the awl on my swiss army knife to make this hole, buy a drill would be fine.

I used a drywall screw to extend the button. I simply broke the end of of the screw with pliers so that I ended up with a screw about ½ long.

I had to use a counter sink bit in my drill to recess the back side of the shell so that the screw head sits flush.

Insert the short screws, then thread on the head of an old Nerf dart. this makes a comfortable thumb button. you will want to secure this with glue once you are sure it is working properly.

This took me many attempts to get right. it would work fine until I assembled the blaster, then the screw head was sticking out to far that it was holding the for button down, so it wouldn't full the tank. that is the reason for countersinking the screw head. take your time.

Step 11: Assemble the Blaster.

This is optional, but I cut a piece of packing foam to fit around the air tank, just for some extra support.

Put the blaster back together as make sure everything works. I had to tweak the firing button position several times.

Step 12: Build Shotgun Attachment

Cut three 3" sections of ½" cpvc pipe. line up the ends of two of them, place them on a flat surface beside each other and glue them together with hot glue. place the 3rd barrel on top of the other two, line up the ends and glue it in place with hot glue. be sure to use enough to fill in the gap at the center of the barrels.

Insert the 1" slip fit to ¾" threaded adapter into the, 1" coupler, and secure with pvc cement.

insert the 3 barrel assembly into the other side of the coupler, it will be a very tight fit.

fill in the gaps with hot glue until you have an air tight seal.

Optional: Paint this attachment. I used charcoal vinyl dye, and orange krylon for the tips

Step 13: Prepare Accessories

Add whatever accessories and attachments you wish.

I painted a Spectre barrel and Raider stock with charcoal vinyl dye, and added a custom made dart holder on top for shotgun ammo and spare mag holder to the side rail