Here's what Wolff Springs shows on their website:
Rating Notes:
Standard Size Models
Factory Rating: 14 Lb. - 9mm, .45 ACP, Super .38 and 10mm
Factory Rating: 12 Lb. - .40 S&W all models except CZ
Factory Rating: 16 Lb. - .40 S&W - CZ Only
Factory Rating: 13 Lb. - CZ 97 .45 ACP (14-16 Lb springs suggested for hardball in CZ97)
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I've run just about everything from variable-rate BHP springs (which are a better fit than the Wolff CZ springs -- which are sized to fit the larger diameter Tanfoglio/Witness guide rod) to 20 lb. springs without problems. I don't shoot as much as I used to (and have been shooting a lot of different brand guns over the years), but found that the BHP springs were almost identical to CZ factory springs, and only get them when buying recoil springs for fulls9ze 75B-based guns.