Copyright International Ammunition Association, 2008. All rights reserved.
Cartridge of the Month August 2008
.38/357 MBA "Short Stop" short range lethal cartridges
Specimen and photos courtesy of Mel Carpenter, sectioned by Paul Smith
The top round shown is the prototype. The middle round is an early production specimen. The bottom round is later production.
The MBA .38 Special /.357 Magnum Short Stop™ revolver cartridge is a spinoff of the less-lethal Stun-Bag™, invented in 1970 by MBA Ordnance Systems Manager Robert Mawhinney. Unlike all other MBA ammunition and devices that fire a version of the Stun-Bag, the Short Stop is lethal at short ranges, not less-lethal. It was designed to solve two problems that sometimes occurred during police gunfights with criminals: a ball bullet fired from a police revolver would pass through its target and injure innocent bystanders, and a ball bullet fired from a police revolver would miss its target entirely and ricochet into innocent bystanders.
"Short Stop" prototype
The Short Stop round was made by replacing the ball bullet in the .38 Special cartridge case with a 1-inch flat canvas bag containing #12 lead shot and weighing about 65 grains (shot and bag). The small bag, one of a series of Stun-Bags™, was contained in a plastic sabot until clear of the revolver’s muzzle. Because the barrel’s rifling caused the sabot and bag to spin, the bag opened up flat due to centrifugal force when it was clear of its sabot, and it struck its target flat. At short ranges of 10 to 20 feet or so, it was very lethal, but its energy dropped off rapidly. By 100 feet, it was spent.
On 19 August, 1971, MBA filed a patent application for the Short Stop. The patent, 3,762,329, was granted on 2 October, 1973. It depicts the prototype cartridge with its pointed-ogive sabot.
According to Robert Mainhardt, the prototype Short Stop cartridge sabot was a ball-point pen cap that just happened to fit perfectly. The series of flat surfaces around the sabot were just part of the cap design, not done by MBA. All of the prototype cartridges seen to date have brass cases with a SPEER DWM HV .38 SPL. headstamp and nickel primers.
The prototype round used a white stun-bag that might be Kevlar, a black rubber disc under the stun-bag, and a brass cup over the propellant.
"Short Stop" early production
During the Short Stop’s early production, MBA used Speer, Inc. yellow plastic shot capsules, reduced somewhat in length, as sabots. The Stun-Bags had one side made of orange canvas and the other of a white cloth of a loose weave, apparently over tinfoil. They retained the black rubber disc under the Stun-Bag and the brass cup over the propellant. Most early production rounds seen have nickel-plated cases, W-W 38 SPECIAL headstamps, and nickel primers with red annulus. However, one early production Short Stop seen has a brass case and SPEER DWM HV .38 SPL. headstamp.
"Short Stop" final production
The final production Short Stop used a roundnose red sabot. The Stun-Bag contained about 55 grains of #12 lead shot inside a clear plastic inner bag, and had both outer sides made from orange canvas. This round did not have the black rubber disc or the brass cup. Instead, it used a polyethelyene plug. It is seen in both nickel-plated and brass cases, either with a red annulus or no annulus. All have nickel primers. Headstamps include W-W 38 SPECIAL, W-SUPER-W 38 SPL +P, and R-P 38 SPL.
The Short Stop was packed in six-round kits inside plastic bags and in 50-round plastic boxes. By 1974 it had been adopted by the USAF for Military Airlift Command flight crews. It would not penetrate the skin of an aircraft, and would seem to be a perfect solution to today’s anti-terrorist airplane cockpit armament.
Reference: Mel Carpenter,Unpublished manuscript notes.
Copyright 2008 by the International Ammunition Association, Inc. All rights reserved.
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Revised 31 July 2008