They might be a little on the weak side (Wolff gunsprings makes great springs for these and it uses standard 75 springs for the mags). Some of the older models of 97 had feeding problems related to mags and feedramps and the company updated them and will fix it if you send the gun back to them. Lots of issues with CZ's come from having crap build up under the extractor claw, this would also cause sluggish feeding issues.