I would suggest that you continue to crimp for now and see what kind of grouping you get, then look into seating the bullets out further if the groups aren't acceptable. You might want to make a chamber cast and see just how much 'throat' the chamber has first. I have two .357 barrels and one of them has considerably more of a throat than the other.
I seem to recall some mention of the .357 needing a crimp in order to get a more effective burn of the powder but this may only apply to revolvers. I would need to check the manuals to be sure.
Brian, in Ohio