First off if your die set doesn't specify that the crimp is a roll then it is most likely a taper crimp. On a roll crimp die you generally will get a nice little radius at the top of the case around your bullet. These aer good for lead bullets. If your getting the flattened look on your test cases then your taper crimping them. This will work but tends to do better on the jacketed bullets with the cannalure. I would suggest that you try to seat and crimp in two seperate operations and when you seat your bullet set it so that you are catching just below the lip of the driving band. If your bullet has got a crimping grove on it then just enough to completely compress the case into it should be suffucient. There is such a thing as too much crimp and you should adjust your crimp die so that the very top of your stroke is the end of the crimp.
I'm sure that others will join in and cover some finer details but this should help you get a better idea.
I hope this sheds some light on your situation.
Mike / Tx