Introduction: HPR Mk. I

My personal war gun, and favorite I've used thus far, this is my High Performance Rifle (tentatively Mk.1).

Step 1: Explanation

In 2014, Zak designed a trigger system for TRs that is capable of reducing dead space to a bare minimum. Dead space is basically the amount of length on a firing pin that does not contribute to its acceleration. A firing pin that only accelerates 3 inches before stopping has more dead space than that of one which accelerates for 7 inches before stopping, assuming they are both the same length. Naturally, more length to accelerate means more power.

The latest TR is perfect for wars, but it has some drawbacks that I attempted to address with this gun. The first issue is the amount of dead space it bears: 5.5 connectors (though I prefer to use the term 'units', and will do so from here on), where my attempt landed me at a comfy 3. Another issue, though mostly conjecture until tested and proven otherwise, is the pin guide.

Oh I can already hear the angry mobs screaming at my door, but let's think about this for a minute. A pin guide requires at least one unit of a pin's length for a connector to tether the two. Generally, a guide is used to keep the pin from bending when it is being held in its cocked position, and when it is traveling to a lesser extent. In motion, I thought the pin would be traveling too quickly for the bend to affect power more than a pin guide's friction and the extra dead space. As such, if the pin can be held in position when it's cocked, a pin guide becomes unnecessary and redundant. So I scrapped it.

The absence of a pin guide left some extra space to play with, so I installed an ammo holder in its place. This provides ease of access to 24 extra pieces of ammo. After using the ammo holder in a war, I don't think Ill ever want to use a gun without one again!

Through several iterations and collaborations between Zak, ooda, and I, this gun is my contribution to the performance pool, and hopefully we'll see many more iterations down the line as I fix its problems and refine its strengths.

Step 2: Gather Parts

Note that these parts are listed in K'nex's standard colors, though I used a slightly different color scheme on mine.


  • Green: 186
  • White: 53
  • Blue: 23
  • Yellow: 4
  • Red OR Tan*: 2
  • Tan: 1
  • Gray OR Black*: 3
  • Black: 5

*As always with performance guns, the stronger rod is preferred, but either will suffice in these cases.


  • Metallic Blue Clips: 17
  • Tan Clips: 31
  • Dark Gray: 21
  • Light Gray: 46
  • Red: 23
  • Green: 8
  • Yellow: 106
  • Blue: 4
  • White: 11
  • Orange: 16


  • Hinge (black end): 10
  • Hinge (blue end): 5
  • Blue Spacer: 19
  • Silver Spacer: 9
  • Ball Socket: 1
  • Y Connector: 20
  • 1" Black Wheel: 6-18
  • Bendy White rod: 3
  • Small Wheel: 5
  • Black Cap (see picture): 4

Before we move on, I'll assume that these numbers are not 100% accurate, as I just counted what is seen in the pictures rather than the gun itself. As always, be sure to go over the instructions thoroughly to figure out what parts you may want to substitute or subtract from your count (18 1" wheels may be out of reach for some people).

Step 3: Barrel

Now then, let's get started with the build. The HPR was designed first and foremost with performance and efficient
use of space in mind. Every part of it serves some purpose, and altering it (for the most part) would make the gun worse. Be sure to follow these instructions as closely as possible, as most alterations would hamper its effectiveness.

Some surface details could be slightly modified to accommodate for comfort or lack of parts, like the 1" wheels on the handle or any of the extra connectors on the blue rods throughout the stock. The end of the stock is really the only part that could be modified, but all the main structure must remain intact.

Throughout the instructable I have placed several notes on images pointing out key information, so be sure to check every image for them!

Step 4: Shoulder Rest / Stock

This is a bit extravagant I admit, but it's the most comfortable I've made for it. You could just as easily make it a square instead, so long as the main structure remains intact.

Step 5: Body

This section is where most of the gun's strength comes from. The 1" wheels are not necessary, but they add a great deal of comfort to the gun. I believe the tires KILLERK uses on his handles will fit this gun as well, so you could use those as an alternative. Personally, I like the tape. If you choose to use tape, put a layer on upside down first, then cover it with a second layer so it doesn't leave a sticky residue on your parts.

Step 6: Bits

I didn't take any extra pictures of the turret because it is very straightforward. If you need any help, follow this link.

Step 7: Assembly

Here we will assemble the gun. I have included several important notes in the pictures, be sure to read them!

Step 8: Firing Pin and Banding

Fairly straightforward.

To make the "indestructopin", follow one of these links:

Step 9: Turret Functionality and Finishing Up

This is a short and simple step demonstrating how to attach the turret to the gun.

Step 10: Problems and Future Changes

The biggest issue with the current iteration of the gun is the slide. It is not nearly as sturdy as I would like and there are also some user-related problems; it is NOT foolproof. When you charge the gun for the first few times, learn where the back of the slide goes, because it will hit the pin stopper if you're not used to it. I have a few ideas to fix this, though have yet to implement them. Another thing to note, you do NOT want to pull back the slide from the wheel. I use the wheel purely for comfort, and it is not sturdy enough to support the force put on the slide.

Above is a video demonstrating how I fire the gun.