RCBS Rockchucker IV Primer Catch

About

Any owner of the RCBS Rockchucker IV knows it's a great reloading press for making high precision ammo, but the primer catch is horrible.  This improved primer catch is optimized to catch every primer and leave extra room where you need it most for your fingers to place and remove cases from the press.

Printing

I used ABS, but PLA, PETG, ASA, etc should all work.  I recommend 3 shells and top/bottom layers with 25% infill.  Requires supports.

Assembly

You will need:

1. Both parts printed

2. 9/16" ID tubing approximately 24" (60cm) long

3. M5 button head screw which is 16mm long

4. Dremel tool + cutting wheel or hacksaw

5. M5x0.8 tap (recommended)

If you have a M5x0.8 tap, clean the 3D printed threads in the hole.  Otherwise, use the screw to chase the threads and clean them up.

Use your dremel cutting wheel (or hacksaw) to cut a slot in the screw as shown in the picture.  Cool off the screw with some water if it gets too hot.

Insert the screw in the primer catch with the head towards the inside and screw it all the way in as shown in the picture.

Cut the 9/16" ID tubing to about 24" and insert the plug at one end. 

Slide the tubing over the spout on the primer catch.

Install the primer catch on the Rockchucker as shown.  

Use a slotted screwdriver to tighten the screw so it clamps the primer catch to the press.  The button head of the screw will align with the hole in the side of the press.  Be careful to not over tighten the screw!  You just want it snug.

You're done! 

Background

The general idea for this model is based on this thingiverse model, but the design is my own.

Updates

• 2023-08-07: Increase angle of spout of primer catch to improve the reliability of the primer dropping into tube.