COL is determined by:
the ogive and meplat of the bullet.
the magazine lips and when they release the cartridge
the feed ramp geometry
the gun's chamber, particularly the throat length.
The manual only lists the COL they used for their gun, and this can only be considered the minimum COL that the data applies to.
The best way to determine the COL for your gun(s) is to load two inert dummy rounds, generally as part of die set-up.
You will load the bullet for the dummy rounds long and remove the barrel from your gun.
All you need to do is just seat the bullet in the case, usually at the SAAMI maximum COL or longer. For the .45 Auto, this is 1.275". You can also use the magazine to determine max COL, since you want your rounds to fit the magazine, seat the bullets deeper until they fit in the magazine (one reason to load two or three dummy rounds so you can verify magazine function).
Then, just remove enough case mouth flare so the inert rounds chamber freely. To do this, "paint" the bullet and case with black Magic Marker/Sharpee. Drop the rounds in the barrel and rotate back-and-forth once or twice. Remove the inert round and inspect it.
Scratches on the bullet means the COL is too long.
Scratches on the case mouth mean that the mouth is still has too much flare
Scratches on the case at the base of the bullet means the bullet seated crooked.
Scratches on the case above the extractor groove means the case has a bulge that was not removed during sizing.
Keep seating the bullet deeper until the round chambers without the bullet hitting the lede/lands/rifling.
Now re-assemble the gun. Load the dummy rounds in the magazine and hand cycle the gun. Do the rounds feed and chamber? If so, you have the max functional COL for that specific bullet. You may continue seating deeper in small increments until you find the COL that is too short to feed. You now know the functional range of COL for that bullet. In general, somewhere in the middle will be best for reliable functioning and somewhere near max functional COL will be best for accuracy.
I wish reloading manuals spent as much page length discussing the importance of case expansion and COL as they do their latest "toys."