My lube extruder was made by Tom Ballard and his design had a threaded plunger so as it is turned it pushes in and the lube also pushes out through a slot just like this one. The plunger on the Paul Matthews design does not seem to be threaded so I wonder if there is something that needs to be screwed in at the back on those threads that actuates the plunger.

Ok, you have my attention... can you explain what the purpose of it is ?
My understanding is that you use it to extrude a lube ribbon that is in turn used to make "grease cookies" that are sometimes used in Black Powder cartridges loaded with paper patched bullets.



























