It's only been in the last year that I've dipped deeply back into the Mark II world, starting with a KMK-678G. Since then I've added two MK-678G, two KMK-678GC, three KMK-10 (one of them the less than 200 factory D & T 10-inchers complete in the case that I stumbled into), and the Mystery Bullseye Mark II I just posted about in hopes of figuring out its source. I have a second KMK-678G on the way, and really need to stop looking at GunBroker.
I started back in 1989 with a KMK-512 that got Tornado Technology's chop & skim to 4 3/8" with "invisible" thread protector treatment in 2010, shown here with my first Government:
It's not quite 4", but it's close, so I can appreciate the nice balance of that length.
Truth is, I almost always shoot suppressed if I can, so I'll probably never compete with any of you for the lovely & rare 4" models, since I would never desecrate one by threading it. Besides, Governments are probably my favorites, at least for now. I also have a Mark IV Tactical Target, and picked up one of Volquartsen's chopped and threaded 3 1/2 inch $100 specials to use on it and other Mark IV lowers.