I agree with 500 Nitro, I own several older Brno's and the safeties all work the same way so its not an issue.. for me at least.

BUT does anyone offer replacement trigger kits for the ZKK600 series?

You can get them to work OK with lots of fiddling and polishing, replacing pins with oversize ones to reduce creep etc but I would much rather replace the whole assembly with an aftermarket trigger that doesn't have the build tolerances of a Russian tractor

While the overall ZKK design is sound, post 1968 Soviet invasion ZKK Brno's took a dive in quality from the heights of the 1950's and 60's era Model 21H and ZG47. Last week I compared a 1966 ZKK600 .270 with a 1976 ZKK601 .308 and the build difference is like night and day, features deleted and simplified for cost reduction.

I believe Timney now make a trigger for the CZ550 but the CZ design is quite different to the Brno ZKK.

Any leads?

Cheers

TM