GUNS: Testing handgun ammunition for the Dallas Police Department back in the early 1970s required some good old ingenuity. Any new ammo the crime lab recommended would have to work well in both service sidearms and snubnose revolvers.

My first column and the next one will relate the little-known contributions of the Dallas County Crime Lab to scientific testing of police handgun ammunition. I was the firearms forensics examiner in the crime lab in the 1970s and ‘80s. At the beginning of my tenure, the standard test of power was how many 7/8-inch pine boards a bullet could penetrate. This was a terrific test if your self-defense concerns involved marauding lumber.

Then there was Maj. Gen. Julian S. Hatcher’s Theory of Relative Stopping Power, a strict calculation based on general conditions. Like the pine-board test, it did nothing to address expanding bullets. These older methods of estimating bullet success have been beaten in print more than any dead horse, so I’m not going to review them here.

Setting A New Standard
The Dallas County Crime Lab’s involvement started innocently enough, and we had many of the resources to accomplish it. We only needed a “trigger event,” and it all started with a phone call.

Although an agency of Dallas County, the lab did most of the crime-lab work for the City of Dallas Police Department, and it had a lot of friends there. One was a gruff veteran captain who was responsible for buying arms and ammunition for the department. At the time, Dallas issued its officers a .38 Special Smith & Wesson Model 10 and whatever lead roundnose (LRN) ammo came in with the best price; this was a situation the captain inherited from his predecessors. He wanted a smarter way to make ammo purchases.

My phone rang one morning in 1972, and I heard the captain’s distinctive drawl. “Hey, Allan! I’ve got this S.O.B. salesman from Winchester sitting across from me trying to sell me a new .38 Special load. He claims New York City is using it.” The words “New York City” struggled off his tongue with the same tone used in a famous picante sauce commercial. “You got any way to tell me if this idiot is lying?” The good captain always put direct communication above the social niceties.

I said I’d see what we could do. The Medical Examiners’ Office, with whom we shared facilities, had just hired Dr. Vincent J. M. DiMaio from the Armed Forces Institute of Pathology (AFIP). He told us how AFIP tested military ammo using ordnance gelatin.

AFIP made long blocks of gelatin using the then-standard 20 percent concentration. A high-speed motion-picture camera captured a side view of the bullet’s dynamic effect at hundreds of frames per second. Then AFIP reviewed the resulting 16mm film on a frame-by-frame basis with image analysis equipment. This determined the volume of the temporary wound cavity produced in the first 15 centimeters (just under 6 inches) as the bullet traversed the block. The theory was that any penetration past 15cm was no longer in a human’s internal organs. They worked out that the volume of the cavity was directly proportional to the amount of kinetic energy (in foot-pounds) transferred from the bullet to the block. Incidentally, AFIP never referred to stopping power; it called the results “wounding ability.”

We wanted to perform similar tests, but we faced a big hurdle: The expensive equipment that AFIP used was grossly outside our budget. Anyone who worked for county government back then knew it was easier to get a new bulldozer for the road district office than crime-fighting hardware for the lab. It fell to me to see if there was a low-tech way to determine energy transfer--and therefore the relative volume of the temporary wound cavity--with hardware at hand. With the exception of test handguns and a decent ammo budget, the best tool we had was an ancient Oehler Model 10 chronograph with a pair of wood-framed photoelectric screens with 12-inch sensing areas.