I called CZ and they said a CZ stock would fit.Ordered a LUX stock for $150 right off the CZ website and it dropped right in.Excellent English walnut.Will reconfigure the the stock to the original 600 style and of course rechecker. Ordered the Lux as it has more drop than the American series .Anybody wants a replacement stock for their ZKK 600 rifle I believe this is the way to go.Also equivelant stock 95% inletted blanks were going for more than this.