What kind of dies BH ?? Are You looking at the instruction sheet ? It usually explains die adjustment methods, & die functions.
The biggest secret to a good crimp, is keeping "all" Your cases trimmed to the same length. All cases, even in new ones (even from the same batch) are not necessarily the same length, & all of them in any given caliber should be trimmed to insure not only length, but also the squareness of the case mouth. Uniformity = accuracy, & constant velocity spread !
Most .45 ACP dies are taper crimp, to leave the case mouth straight & square, because they headspace on the case mouth. Therefore it is extremely rare to need to trim semi-auto cases. They will actually "shorten" ever so slightly, from slamming into the chamber . Some will eventually become too short to fire reliably, as after "many" uses they will seat beyond the firing pin reach.