U Bullpup Hardware Kit

(2 customer reviews)


Contains all the hardware needed to assemble a U Bullpup (a design by captainslug).

*Blaster is not useable without a foregrip attachment*

Aluminum TriggerMain (+$15.00)
Aluminum Sear (+$20.00)
Aluminum Pcap Plate (+$15.00)
Aluminum TriggerD (+$15.00)
Aluminum TriggerLink (+$15.00)
Carbon Fiber Wrap (+$15.00)
Railgasm Hardware (+$2.00)
Product total
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Grand total


– Contains all hardware needed to assemble a Nerf U-Series Bullpup, designed by captainslug on Thingiverse.
– Assembly instructions provided by captainslug: Bull Pup assembly instructions.
– Includes ramrod with o-ring cutout by default, so no upgraded ram is necessary
– Compatible with cutdown Caliburn springs and Longshot springs
– Springs offered as kg ratings are Longshot springs
– Add-ons sold separately including top rail railgasm hardware
– Printed parts available here
– If ordered with 509 or 495 barrel, will include barrel adpapter
– Length of spring included is: 9″ K31, K26, or 8-3/8″ K25, 788 springs.
– Hardware included is based off of v4 Talon Claw hardware. Similar to v3, but the top rails and priming bars are about 1/2″ longer. Cross compatible to captainslug’s original files with the exception of the top rail needing to be a hair longer. You can download a modified rail segment file here.

– Additional springs can be purchased here
– Railgasm
– Scar Barrel
– Ported MuzzleBrake
– Aluminum internals
– Varying barrel types
– and more!

Printer Files: 
Access to files for printing your own parts available here: Print Files Download
– Pcap plate requires modified Pcap print available here.
-Modified rail segment file download here.

Special thanks to Captain Slug for the great design. Used with permission.


Additional information

Weight 2.0625 lbs
Dimensions 10 × 2.25 × 2.25 in

K26, K25, 788, K31, 8kg (+$6), 10kg (+$6), 18.5kg (+$6)

Spacer Tubing

Black, White, Metal (+$12), Carbon Fiber (+$20)


Short Dart, Full-length Dart

2 reviews for U Bullpup Hardware Kit

  1. Matthew Smith (verified owner)

    Had everything for my build with the 3D printed parts kit. Used the 18″ .509 barrel, 18.5kg spring, Acetal plunger and pusher and all the aluminum upgrades. Shoots lazers at 285 FPS!!!! Going to get a couple other springs to go with it to be able to dial it back for other game types.

  2. kenneth.buckingham (verified owner)

    The hardware is modified from slugs design, you have to use some modified files to accommodate, if you want to install a upper rail.

    The black hardware is only sort of enough for the outside, and the long 10-32 are sockets not buttons, so they won’t work in some areas of the blaster.
    I also never received the normal silver hardware for use internally so watch out for that.

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