It depends on where you measure your OAL. Heavy recoiling rounds (especially in light hunting rifles) pound the ammo that is in the magazine against the front of the magazine and frequently deform the tips. I haven't found any evidence that the bullet gets pushed in any deeper but the tip does get smashed down a bit, there by reducing the OAL of the cartridge. However, the best way to measure OAL is at the ogive of the bullet and that measurement shouldn't change any. Also, the deformed tip shouldn't degrade your accuracy if you are hunting inside of 500yds. Past that, every little bit starts to make a difference.
I have several sets of the Lee Collet dies that my Dad purchased for us before he passed away. He really liked them and I think they get a bad rap unnecessarily. I think Lee needs to charge about fifty bucks more per set and then maybe guys would like them more. I have had good luck with them. If you are concerned about your hunting ammo, pick up a Lee factory crimp die. You will need to experiment with it to make sure that your accuracy remains acceptable but most times it does depending on what bullet you are using.
I have RCBS, Redding, Hornady, CHC and Lee dies and I find myself using the Lee dies quit often.
Good shooting,
Tom