WHAT DOES 38 CALIBER BULLETS MEAN?

Those people rolled cannelures can control your option of what bullet goes in what case. I've lots of aged Remington cases that have an exceptionally large cannelure close to the case mouth. This cannelure seldom is completely ironed flat just after firing and resizing.I just bought some 158 gr SWC bullets that happen to be pure guide. How am i abl