OAL for .45acp
The ideal OAL for a .45acp reload is best determined by using the barrel as a case gauge. Every barrel may have slight tolerance differences in the throat area, so it is best to use your own barrel to set the OAL. I do what is called the drop test. I remove the barrel, hold the barrel in one hand with the muzzle pointed to the floor, then drop a reload in the chamber. The reload shoot enter freely, and not bind going in. The base of the brass case should be even or flush with the hood extension. It the bullet seats lower than the end of the hood, try a bit longer OAL for that bullet. The ideal length will be one that allows the reload to sit flush with the hood extension. So why, would you ask, is this best? The answer is positive and uniform primer iginition. If the round is seated flush with the hood of the barrel, then the round is pretty much flush with the breech face of the slide. If the cartridge is not flush, it can move forward under impact of the firing pin, and may not allow uniform and consistent firing pin hits. This may lead to erratic ignition of the primer. The .45 cartridge headspaces on the case mouth. Unfortunately, not all cases will be the same length, and the taper crimp will also slightly change the way the bullet seats in the chamber. By adjusting the length of the bullet, so it just touches the lands and grooves, allows a secure base for the firing pin strike, and won't allow the cartridge to move in the chamber. This is often recommended in reloading manuals to improve accuracy. Adjust the OAL for your barrel, and don't go by what people use in their barrels....each barrel has its own specs. A worst case scenario would be a slightly shorter than normal brass case with a "high" primer (not fully seated) with a heavy firing pin spring. If the case were to move slightly forward, this lessens the impact of the already heavy firing spring....add the movement of the primer in the primer pocket, and you may get a "Failure to Fire" that shows a light primer hit.
