.38 Automatic (using Hornady bullets)
Date: Jan 07 2015
The .38 Automatic (aka .38 ACP, .38 Colt Automatic) dates back to 1900 and was developed by John Browning, along with the Model 1900 Colt Automatic pistol. Original factory loads were advertised to push a 130-grain bullet at 1,040 fps from a 6-inch barrel. The gun and cartridge were intended to capture military interests but were never officially adopted as the forthcoming Browning designed Model 1911 and .45 ACP pistol cartridge were better suited to those needs.
Beginning in 1929, Colt chambered the Model 1911 for the .38 Super Automatic, which had the same external dimensions as the older .38 Automatic, but was loaded to much greater pressures. Using .38 Super ammunition in the Colt Model 1900 and 1902 pistols is dangerous, and should never be attempted. However, .38 Super cases are suitable (and readily available) for assembling handloads that duplicate early .38 Automatic pressures and velocities, which allows vintage guns to be put back into use. New Starline cases were used to develop the accompanying data.
Industry specifications have caused much confusion when handloading the .38 Automatic. For example, barrels have been made with groove diameters measuring .355, .356 and .357 inch. The accompanying data includes Hornady 9mm bullets measuring .355 inch and .38 Special/.357 Magnum bullets measuring .357 inch. It is suggested to slug your barrel and determine the groove diameter, and match bullets accordingly. Or try both bullet diameters and determine which gives the best accuracy in a given gun. When using revolver bullets, the listed overall cartridge lengths should be observed to allow cartridges to function correctly in the magazines and prevent the bullet from contacting the leade.