Being white box I doubt it's crimped, if it is you will see the crimp around the primer pocket. There are a few tools you can use to remove the crimp, RCBS has a primer pocket swager that you use in your press, Lyman, Hornady and RCBS have primer pocket reamers. I've used the Swager and Hornady reamers on some 9mm LE/military brass I bought a while back.
If you can post a picture of the cases it would help. The one below was borrowed from another site, but shows the crimp on some 223 brass. If your brass doesn't have the ring just outside the primer pocket it not crimped.