... I personally like it (ZKK602) more than the CZ action. That's not to say l dislike CZ. I just like the ZKK602 comparatively more ... l would opt for a CZ action. If l was opting for a .500 Jeffery or .375 H&H Magnum , l would opt for a BRNO action
This is fascinating reading....
Actually, the ZKK 602 and the CZ 550 are exactly the same action, made in the same CZ factory, with the same machine tools.
The CZ factory used the Brno trade name during the communist years because it had accrued a good reputation in Europe before WWII. After the communist era CZ was privatized and used its own trade name. They are apparently starting to use the Brno trade name again for some product lines. Not all ZKK 602 had the fold down peep sight, and those that did not are indistinguishable (save the brand) from the CZ 550, although through the successive generations, the bolt handle profile has changed a little, and the bottom metal has changed, replacing the ZKK trigger that is articulated on the trigger guard, with the current trigger unit. Some prefer the old trigger, some prefer the new trigger. I had both, both work.
Because these are not cast actions, and they are not CNC machined, but still made on machine tools, they tend to have a few machining marks and burrs here or there, which need to be cleaned up for perfection. I certainly do not understand why they do not deburr at the factory, but I can personally live with it and do it myself considering the tremendous value and the uniqueness of the value.
Rigby of London used in succession the Brno-marked and CZ-marked actions to build their own Rigby rifles (and removed the Brno or CZ markings) during the long time before Mauser very recently restarted building magnum length actions. Whether one uses a Brno-marked ZKK602 or a CZ-marked 550 action to build a rifle makes zero difference whatsoever.
The imaginary CZ "issue" is perpetuated by folks who visibly have never held a CZ 550 and are mostly repeating each others. This is regrettable. It personally makes me smile when folks bash the $950 factory CZ for not being as smooth as rifles that cost twice or three times as much, while not realizing the incredible value they have in their hands (true magnum length, double square bridge, build in scope mounts, integral rear sight island dovetail, barrel band front sight, steel bottom metal, 5 + 1 capacity in most calibers, etc.).
To each his own, I guess...