Whether 'tis nobler in the mind to suffer
The slings and arrows of outrageous posters
Or to take arms against a sea of traditionalists,
And by opposing end them? To shoot: to crimp;
No more; and by a crimp to say we rolled or collet.
The powder smell and the felt recoil
That flesh is heir to, 'tis a consummation
Devoutly to be wish'd. To reload, to shoot;
To shoot: perchance to shoot true: ay, there's the rub;
RealGuns just did a little experiment with crimping and are suggesting that crimping may be totally unnecessary. We may have been doing it more out of habit than scientific need. I've always rolled crimped my rimmed pistol cartridges. I might cut back some on my crimp on my .357mag and max. Probably extend the live of the brass by a couple of reloads. One reason to crimp not given a lot of coverage is how well the bullets hold up in handling. Though we're talking +100# of force to move these particular tested bullets. That should hold them during transport, storage and handling.
http://realguns.com/Commentary/comar184.htm