HQ-E2 Compressible 2-Piece Bolt Hold-Open Magazine Follower

Update Sep 27: Added version with a magnet pocket (instead of press-fit, which is sensitive to magnet dimensions and print tolerance). Takes 1 M3 nut and 1 M3x8mm socket head screw.

The HQ-E2 bolt hold-open requires the magazine follower to have a magnet positioned about 26mm below the top of the follower. This makes the follower taller and reduces dart capacity by 1 in any Talon magazine. My version allows the magnet to sit at the correct position when you're down to 1 dart or empty, and compresses when the magazine is full.

Requires 2x 0.3mm WD / 5mm OD / 25mm L springs. These springs put the magnet at the correct height against the force of the original magazine spring (I'll call that the main spring). Some pen springs may work, but YMMV a lot. Too weak or short and the magnet sits too high. Too long or firm and the magnet sits too low & darts get squished in a loaded mag. Too thin and they might buckle.

The 2 round springs are not fixed to the follower, so when installing hold the magazine body vertically and gently slide the follower/spring assembly up, being careful not to let the main spring catch on the bottom edge and release, which could pop-up the top half and dislocate the round springs. I suggest practicing on a clear magazine so you can see what's going on inside.

Use 1 M3 machine screw to fix the main spring to the bottom of the follower. This should prevent the main spring from buckling at full compression. I'm not sure if that's something that actually happens but stock Worker magazines all have a screw here. Don't over-tighten!

These don't need much mechanical strength so say 3-4 walls and 15-25% infill seems plenty good enough.