Over-all Length (OAL) is important when we're reloading for more than one gun, especially if one of those is a repeater. If you get the cartridge too long for the gun, it won't cycle.
For example. This .357 cartridge, at 1.570 inches, works just fine in my Marlin 1894C.
On the other hand, this nearly identical cartridge at 1.616 won't go through the 1894. It's too long. One cartridge is 0.046 inches longer than the other and that makes all the difference.
You've been warned.