I've read of the hard primers issue with Yugo 7.62x25. Early off, I suspected it was developing a bad reputation for being unreliable in general.
I sold my CZ-52 before I stocked up on this ammunition. I can tell you this ammunition is 100% from both my M57s. I can only guess this ammunition was intended in part for the excellent Yugo M57.
If you're sticking to the CZ-52, you might be better served with 80'-ear Romanian or 50's-era Polish FMJ. Both worked well from my CZ-52 when I had it.
I would think there might be some spring kit available for the CZ-52, but unless you needed it for proper function with other ammunition, I wouldn't bother. I just wouldn't use Yugo ammunition for that particular pistol. Since you already have the ammunition, you might need to get a Yugo M57.
I stocked up as it was so darn cheap and made by PPU and have a copper jacketed lead bullet and brass case. If felt the need for more 7.62x25 military surplus, I'd probably purchase more of this rather than Polish or Romanian milsurp (which I also have and enjoy).
Seems accurate (from an M57 anyways) out to 25 yards. I plan to chrono these loads within a couple months.