.38 Super Automatic Handgun (using Sierra bullets)
Date: Jul 12 2016
John Browning designed the Models 1900 and 1902 Colt pistols chambered for the .38 Automatic (aka .38 ACP and .38 Colt Automatic), which originally pushed a 130-grain bullet to 1,040 fps. Beginning in 1929, after the development of the stronger Model 1911 pistol, Colt introduced the .38 Super Automatic (aka .38 Super and .38 Super +P), which was externally identical to the older .38 Automatic cartridge but loaded at much greater pressures. Early ballistics pushed a 130-grain bullet to 1,280 fps.
In 1974 the industry adopted the “+P” designation for cartridges that have two pressure limits, which led to the “.38 Super +P” designation to help prevent it from being chambered in older Colt Model 1900 and 1902 pistols, which is dangerous and not recommended. Current industry maximum average pressure limits are established at 33,000 CUP, with none of the accompanying loads exceeding that figure.
The industry has created some confusion with the .38 Super, as barrel groove diameters have been produced at .355, .356 and .357 inch (depending on manufacturer and date of production). All of the accompanying data was fired using Sierra bullets that measured .355 inch and produced top accuracy from a Kimber Model 1911 test pistol.
Bullets should be seated to the correct overall cartridge length, then as a separate step, a taper crimp applied. The crimp applied to most factory loads (measured with blade calipers at the case mouth) is around .375 inch.
Several powders duplicated or exceeded factory load performance (accuracy and velocity combined) with Alliant Power Pistol, Accurate No. 7 and Vihtavuori N-340.
None of the accompanying data has been pressure tested. Some maximum loads may exceed maximum average pressure limits established by SAAMI for this cartridge. Never begin with maximum loads. Always begin with “start” loads and watch for signs of excess pressure before increasing powder charges.
In spite of much .38 Super data being published containing small rifle primers, Winchester Small Pistol primers were used exclusively here and gave proper ignition and handled the pressures without issue. If this data is shot with small rifle primers, pressures will increase and powder charges will necessarily need to be reduced.