I got all my supplies on fri. to start loading for my carbine and went out this morning to set it all up. All the brass was sized and trimmed to 1.280. I belled the mouth to about .331 O.D wich is enough to get a bullet just barley in the mouth. I have some factory Rem. and Aguila ammo that I measured the mouth on to use as a guide for the bell and crimp. Both factory loads are .329-.330 at the mouth so I went with .331 for my bell and .330 for crimp. The bullets are seated at 1.280. Now here is the problem. I used basically the same procedure when I was setting up for .45 ACP and everything works fine. My neighbor told me to check the crimp to make sure the bullet doesn't set back when chambering the .45 buy putting the round in the mag. and letting the slide go into battery, then measure to see if there was any set back. This worked for the .45 but is not for the carbine. The COAL actually grows about .001-.003 inches. The factory rounds will not change COAL even though the mouths measure the same on them and my handloades. Any advice? Is it even worth worrying about?