This is part based on https://www.thingiverse.com/thing:2809150 but redesigned from scratch for better fit and for 3D Printers (no aluminium required).
Use PETG or better.
You should use spring and ball or screw with rounded head as a lock mechanism.
IMPORTANT:
in some cases you have to readjust black arm (safe rod guide). just loosen black screw and pull arm anticlockwise a little.
BTW. Here it is my site for reloads and reloaders http://reloaddata.pl
Printer Brand: Prusa
Printer: i3 MK3
Rafts: No
Supports: Yes
Resolution: 0,15mm
Infill: 20%
Filament: Prusa PETG
Notes:
See attached images for best print orientation
The author marked this model as their own original creation. Imported from Thingiverse.