NERF Retaliator plunger tube expansion

Most of the Nerf Retaliator modifications I have done are using common parts or kits made available through after market retailers or vendors. After installing a few pump grips, stefan kits and upgraded springs I figured I would try my hand at a more sophisticated mod, a plunger tube expansion. The stock Retaliator contains a relatively small capacity plunger tube. I measured it’s volume at about 30cc. There are examples of plunger tube replacements in Retaliators using Longshot plunger tubes and plunger heads, but I felt weird using the Longshot parts and essentially trashing a Longshot to upgrade the PT on my Retaliator. So I read a brief mention of using a 100cc syringe instead. This post walks you through my PT replacement using a common 100cc syringe.

This is a project I’m actively working as of June 2017. Keep checking back for updates as I make progress 🙂

Back to dart blasters!

 

References

Here are a few references I drew from:

Summary parts and materials list

Parts

  • NERF Retaliator
  • 100cc syringe
  • Lexan sheet
  • 35mm o-ring

Tools

  • utility knife
  • dremel
  • orbital sander
  • file
  • calipers

Supplies

  • Loctite Plastic Epoxy
  • masking tape
  • dremel cutting wheels (I seem to break a few of these with every project)

Sourcing the Syringe

I found a Measure Master Garden Syringe on Amazon. It looked like it might work, so I ordered one and when it arrived I was quite happy to see that it would indeed work. Here’s the syringe next to the stock Retaliator plunger tube:

With the plunger removed:

Making cuts to the plunger tubes

I roughed out the approximate size of the cut down tube that I thought would be the correct size and marked my cut line with a piece of masking tape. This worked out to about 80cc:

There are two cuts I’m going to have to make to the front of the plunger tubes. I have to remove the front of the stock plunger tube and create an opening in the new syringe that will accept the cut down stock piece.

I used a box cutter to remove the tip of the syringe. I then used a dremel to expand the opening so it would allow the tip of the stock plunger tube to fit through the opening:

 

Then I cleaned up the lip of the stock plunger tube and cut the front off the front. I used my orbital sander to clean up the base of the cut, and I scored the lip that will press against the syringe wall so I can get a better gluing surface.

 

I then used my dremel to cut around the 80cc line shortening the syringe tube:

That’s it for the plunger tube cuts. I now have the front of the stock tube, a cut down syringe, and an opening sufficient to receive the front of the stock tube.

 

For reference, the inner diameter of the new syringe based plunger tube is about 35mm. I’ll use this measurement when sourcing my o-ring:

The plunger

This was the biggest issue for me. Most plunger tube replacements rely on pilfering a plunger from a longshot. Since I’m trying to not use a long shot for this project, I have to figure out how to come up with a plunger based on extra parts, or parts that I source from 3rd parties. I considered:

  • making my own plunger head out of cut polycarbonate.
  • using the plunger from the syringe
  • buying an artifact long shot plunger head
  • rolling my own with a 3D printer

After extensive experimentation, I decided to print my own plunger. I based it off the stock plunger, and added a long shot like plunger head. The current working model looks like this:

I am experimenting with the catch area currently. The main shaft is working well guiding an upgraded spring, but I am having difficulty with the print quality on the catch portion of the plunger. The seal seems good on the o-ring and head design. I’m using a 35 mm o-ring that is 2.5mm thick. I’m using 100% infill on all my designs. Currently I’m on about 10 revisions.

Cushioning the plunger head

Now that we have a plunger tube and plunger built, I wanted to provide some cushion to the front of the plunger tube to absorb the impact of the plunger head. I intend to test a variety of springs with this expanded plunger tube. I have a worker 7.5 kg spring, a Titan 9 kg spring, and a 10 kg spring that will generate considerable force. I’m going to custom cut gasket material that will act as padding. Here’s the material I picked up from Home Depot:

The inner diameter of my plunger tube is 35 mm. I measured out a 17.5 mm radius that I transferred to a compass:

I then marked circles on my gasket material:

I then marked an inner circle with a 17 mm diameter  8.5 mm radius for the center opening:

Using an Exacto knife I removed the material from the inner opening of the gasket. I made four of these gaskets so I could experiment with the width of the padding. Here’s what it looks like in the front of the plunger tube:

Modifying the shell

Coming soon

Installing the plunger tube

Not quite there yet…

Test fit!

Chronograph results

Shortening the stock attachment point

The priming indicator on the stock Retaliator attachment point is a component I don’t intend to use. I saw that Worker offers a shortened stock attachment plate, so I thought I’d try cutting down the stock stock attachment point (heh) and potentially shorten the plunger rod as well. Here are a few images of the before:

And after following a quick cut with the dremel and sanding with my orbital sander: