An unfired round of 45 ACP (WCC 71) measures .4695 at the point just above the web. After firing it measures .477. After a trip through my RCBS sizer, it measures .469.
So, we have the brass expanding .008 at it's largest point. Will that make a difference in how the round feeds and functions? Maybe so in some guns and maybe not in others, but the object is to have handloads with the same specs and performance as factory ammo. You don't get reports of good 1911 pistols choking on good factory ammo.
I still enjoy reloading ammo with the Lyman 310 tool, which only neck sizes cases, even handgun cases. With this set up, even the 38 Special cases must be used in the same revolver in which it was fired. Go to another handgun and it may or may not chamber. As a result I FL size all 38 Special brass as you don't know where it might end up. The same is true for the 45 ACP case.