I was told (here) that my Pre B CZ85 had a threaded barrel bushing.
Huh. Learned something new.
Had no idea there were older CZ's with threaded bushings. The two CZ's I own that have bushings are the normal ones that started with the roll pin through the front sight, staking the bushing in place, though my 97 has the E conversion with the threaded 1911 match bushing.
OP, if the bushing is uncooperative, put the upper in the freezer. It will tap out fairly easily.
Thanks.
What I do and has worked for me:z
Drill a hole in a block of wood large enough for the bushing to fall into.
Take a towel and cover the muzzle area.
Place slide with towel onto the wood and hole.
Place on a concrete floor so there is very little flex.
A few blows with large and it's out. Even the really stuck ones come out like this.