Nerf Rival Kronos Short Dart Conversion Insert (Bonus Spring Spacer)

If you want to enable your Kronos to fire short darts but don't want to pay for a kit, this insert does the job. Plus, the modification is completely reversible and does not require permanent changes to your blaster.

Only 3D printed parts (and PTFE tape for a better seal) are needed. The one screw used is taken from the air restrictor.

A bonus spacer is added to increase spring preload.

This modification requires the removal of the air restrictor.

Janky chronograph (analyzing slo-mo footage frame-by-frame) reads roughly 140fps with the stock spring.

Printing Tips:

• Choose sharpest corners for the Z seam setting, otherwise some bridging may not work
• None of the models require supports, maximum overhang present is 60 degrees
• All models should already be oriented for printing, assuming Z up
• Make sure your printer is well tuned since many features interface directly with the injection molded components (try to minimize elephant's footing as well)
• Inner walls before outer can help with overhangs
• Cubic/Cubic Subdivision infill recommended with at least 10% density
• At least 2 walls, up to 4 for the spring spacer
• STEP file containing all parts is provided if you need to tweak it (printer tolerances, different dart size, longer barrel, etc.)

Assembly Video: https://www.reddit.com/r/3Dprinting/s/qopy4f289v

Post-Processing Tips:

• Wrap a couple layers of PTFE tape around the insert at the region right before it steps down in size, 2 layers of tape should suffice

Usage Tips:

• Insert darts tip-first as far forward in the slot as possible, then push the rear of the dart down into position