.45 ACP (using Hornady bullets)
Date: Apr 23 2020
The .45 ACP cartridge was designed by John Browning around 1905 for an auto-loading pistol intended to meet the needs of the military. In effect, it was a .30- 03 case cut off to a given length. Ultimately, it ended up his famed Model 1911 pistol, and today is widely popular among military, police and civilians where it has earned a superb reputation as a defense, sporting and target cartridge.
Due to the short powder column and capacity, small changes in powder charges can increase pressures rather quickly. Maximum loads should thus be approached with caution. Caution should also be exercised when seating bullets. Be certain that the overall cartridge lengths are exactly as listed, as bullets seated deeper can increase pressures to dangerous levels, while bullets seated out to a longer length may not fit in magazines or feed properly.
Since the .45 ACP headspaces on the case mouth, taper crimping is required. Crimped cases should measure .470 inch at the mouth (which can be checked using “blade” style calipers). That will offer enough bullet pull to aid with powder ignition and prevent bullets from being deep seated (a potentially dangerous scenario) when slammed into the feed ramp.
When using Hornady swaged lead bullets, including the 200-grain SWC and 230- grain LRN, barrel leading often occurred at velocities exceeding 800 to 850 fps in a Ruger Model 1911 test pistol (and was also observed in other guns). With both bullets, the best accuracy was usually observed at 700 to 800 fps, which limited barrel leading and allowed the lead bullets to correctly engage the shallow rifling associated with this cartridge.
The accompanying data was developed with Winchester Large Pistol primers. In recent years a change to small pistol primer pockets has been observed, primarily in “lead free” and “indoor” target loads. In these instances standard Small Pistol primers may be substituted, but velocities are usually around 10 to 40 fps lower than listed here.