Ring end gap

Have you checked more than one ring and bore?
A few comments... a
s Darren mentioned make sure the piston to wall is within KB's specs.
Make sure the part number on the ring set is correct. It sounds like you might have a +.030 over ring set rather than +.040. You're best bet is to get a set that is designed to be file-to-fit.
Use the KB sheet for the recommended top ring gap. For the second ring add .003-.004 to the recommended gap.