Start with stock Nerf Swarmfire. I won't be doing a voltage mod.
Start by taking off the stock and the battery door.
Next, remove the screws holding the yellow over casing on. Gently remove the two yellow halves and set them aside. Be sure to keep track of the screws.
Remove the remaining screws to open up the blaster.
Next, we're going to open up the electric firing mechanism. Remove the three screws holding these together, then gently pry it apart by releasing the plastic catches around it.
Pry loose the barrel. See those smiley face things? They are air restrictors and need to be removed.
The best way to remove them is using a rotary tool, like a Dremel. Cut each one of the restrictors out and throw them away. Be sure to use safety glasses, as the plastic likes to fly everywhere.
If you are planning on painting the gun, now is a good time to sand, prime, and paint the barrel.
Next, we are going to remove the air restrictors from the plunger assembly.
Use the Dremel to cut out the air restrictors. Be sure to clean all the dust out of this particular part after cutting. Use a drop of hot glue on the air release hole to seal it.
Then we will improve the seal of the black O ring. Put some Teflon tape on this piece, then place the O ring back on.
Now you are done with the internal mods. Carefully put the firing mechanism back together, and reassemble the gun. Test fire to make sure it is working. Note the longer range and louder sound.
Once the gun is back together, it is also fun to paint it. Makes a cool gift.