It does loosen up some, but you can either tighten the screws a little more or trim off some of the rubber grommets to get the shell tighter to the leather. But honestly, the way I look at it is your belt will be aiding in the retention too. I've never had any issues with it. But I believe Raw Dog has a 30 trial period. If you don't like it, ship it back for a refund.
L8R,
Matt