The Ported Piston Plusbow

What's up, my people?

It took a while, but I've finally finished my first Plusbow! It is designed by the one and only Captain Slug. For those who don't know him, Slug possesses the mind of a genius, a love for Nerf, and a hatred for Dremels. Though he is a gentleman and scholar, I still found several way to improve upon his design. Here are my changes:

• HDPE grip
• Solvent welded front bushing
• Longer screws for everything
• Extension spring instead of ghetto rubber band
• Ported Piston plunger head
• Plunger padding
• Smaller holes at the sideplate connection points

Here's Slug's original creation for reference:

Now let's get down.

Writeup:
Start by playing some Tetris and placing your templates as compact as possible. The pistol grip template should be placed on 3/4'' HDPE and the plunger head template should be discarded:

You know how it's done--drill all the holes then slice and dice! I drilled one of the holes in the trigger close to its corner to prepare for an extension spring. Quality scroll saw blades make a world of difference for this kind of work:

All four of the holes in the grip should be 7/64'' and tapped. If second screw from the top of the grip was moved down 1/2'', it would be so comfy!

Chop the Delrin down to size then drill and tap both ends of each rod. Remove all the protective plastic off the polycarbonate and sand down all rough edges. Expand any holes if necessary. Clear is beautiful!

After assembling the catch mechanism and butt stock:

I used longer screws than the instructions to insure that the rods wouldn't budge. I then assembled the grip and attached the sideplates to the grip and stock:

Here are some glamor shots of the trigger system:

Extension springs are much classier than rubber bands!

Everything in place but the power plant:

At this point it's time to prepare the front bushing. I solvent welded it into place and plugged any leaks with quick-setting epoxy afterwards. You can see the mark I made for the threaded rod:

Use your two nuts and rod to penetrate the tube. Let me rephrase that--tighten two hex nuts together on the threaded rod and crank it into place. Glue around the threads to prevent air from leaking through:

The one nice thing about having a 1/2'' plunger head compared to the stock 3/4'' one is that I get to slip in 1/4'' of plunger padding! I have read of people cracking their sideplates at the connection point with the front bushing, so I've compensated accordingly:

Most of the holes in the sideplates I drilled with the 1/8'' drill bit rather than the 9/64'' bit to get things as tight as possible. The result is something extremely sturdy and much lighter than I anticipated. Kudos to Captain Slug for creating something timeless, elegant, and powerful as hell:

Final Thoughts:
I gotta say--damn this thing shoots insanely hard! Not to mention, the looks are absolutely stunning. It wasn't that hard, but it just took a lot of time and patience. For those that doubt the effectiveness of the ported piston, here's the max fps for ya:

Hot diggity dizzamn! I also confirmed something that people have been saying in the NIC for a while now--that perfect seals don't matter. My plunger slams into the front bushing pretty hard even when I plug the muzzle, but as you can see my velocity is still scary high.

Something I would change about the design:

This would eliminate the only real ergonomic problem with the grip, while still maintaining the same structural integrity. That screw loves to snack on thumb meat. Anyways, I hope you guys enjoyed my second foray into homemades!
~T