I have two Whitworth Express 375H&Hs, two Interarms Mark Xs, and a Remington 798; all of which are great shooters.
I've heard several times about people getting the actions on their Zastavas "slicked up", but I've never fully understood what all that entails. Is it mostly just polishing certain metal work, and is this something you can do at home? Thanks!
I've owned 4 Zastava made rifles (Whitworth 270, 375, two 458s),
Yes, an action can be slicked up at home.
Brownell's has made a Bolt Raceway Polishing Tool, that you wrap with fine emery cloth (600 grit, then 800, then 1000) and run it through the bolt raceways along the action, avoiding grit and shavings getting into the locking lugs. Clean thoroughly afterwards.
I use boiling hot water with a couple of drops of Dawn soap, on a hot sunny day, and douse the rifle thoroughly so that all the crud washes out. The water needs to be nearly boiling so that the steel becomes almost too hot to touch. The rifle should be bone dry in less than 5 minutes.
Then oil the rifle thoroughly (I like CLP).
Another method is using FINE valve grinding compound with a soft cotton wheel on a Dremel tool. Hit the raceways and top and bottom of the magazine feed lips, and the feed ramp. You DON'T want to change any dimensions, just remove fine machine marks. Wear eye protection, because some will fly into your face.
You can coat the bolt raceways with Flitz polishing paste and work the action several hundred times (watching African hunting shows). You must remove the firing pin mechanism from the bolt and trigger so that these tolerances are not changed. Do NOT let any abrasive compound get into the locking lug recesses.
Some skilled gunsmiths can do this for the locking lugs, using proper gauges and skill. Not at my skill level.
I have used these methods for a rough from the factory CZ 550 416 Rigby, and a mid 2010s Ruger 77 African 223.
It helped a lot.
While these methods take some time, it's not difficult, and in a way is like cooking, time, temperature and method.
My Whitworth 458 is pretty smooth as is (I owned 2 and kept the smoothest one).
I would buy another Zastava made rifle in a heartbeat, using these methods, at the right price.