Less is More: The IPSC Power Factor

American Handgunner, Nov, 2001 by Charles E. Petty

Diligentia, Vis, Celeritas-- accuracy, power, speed. This is the motto of the International Practical Shooting Confederation (IPSC), encapsulating the three vital aspects of practical shooting. Speed and accuracy are skills present in the shooter, but power is an attribute of the weapon. Power, as the concept applies to practical shooting, refers to the capacity of the cartridge to impart a fight-stopping blow to an adversary.

To ensure that the cartridges used in practical shooting competitions are suitable man-stoppers, the rules call for a test of the competitor's ammunition. Originally, this was done by momentum on a hinged steel plate called a "ballistic pendulum."

The match organizers would shoot the ballistic pendulum with a "standard" gun and load, usually a Colt Combat Commander with 230 gr. hardball for "major caliber" and a Browning Hi-Power with 124 gr. ball for "minor caliber." Competitors would have to equal or exceed the travel of the pendulum with their match ammo and gun to "make major."

Hardly anyone willingly shot minor caliber because the scoring rings on the IPSC target penalized a shooter for anything but perfect hits with a lower score for minor.

With the advent of affordable and reliable chronographs, the cumbersome ballistic pendulum was relegated to the scrap heap of IPSC history, along with stop plates and Rhodesian walls. Chronographs were used to test competitor's ammo to meet a "power factor" of either "major" or "minor." Major equated to the old 230 gr. hardball out of a Commander; minor corresponded to ball ammo Out of a Hi-Power. The power factor of major was set at 175 and minor at 125.

The power factor is simply bullet weight in grains multiplied by velocity in feet per second, divided by 1,000. This is a variation of the calculation for momentum. The product is divided by 1,000 just to make the answer come out in a nice little number. There are no units assigned; it's just a number.

The original power factor of 175 was based on a practical average of a Commander's velocity with hardball, which was between 775 and 800 fps. The 175 number allows just a little safety margin within the actual values of 178 to 184 for the velocities shown.

Making the power factor with a .45 ACP really wasn't a big deal until a young hotshot by the name of Rob Leatham popularized the .38 Super for IPSC. The common factory load of a 135 gr. FMJ bullet at 1,200 fps wouldn't "make major," but some handloads with heavier bullets would, although nobody wanted to talk about the pressure levels. The .38 Super produced major power factor scores with minor caliber recoil-- a perfect solution to "accuracy, power, speed."

The New "Major"

Now, after several years of work, 15 members of the President's Council of IPSC have come up with a whole new lineup of categories and power factors. President Nick Alexakos said the change was due to the dynamic nature of practical shooting: "This is not a stagnant world. We must evolve or die."

Reflecting the international nature of the sport, Alexakos referred to the difficulties of air travel and possible future roadblocks to shooting abroad. Carrying enough ammo for a big match can result in steep excess baggage charges. Nor is it beyond the realm of possibility that an airline, acting unilaterally, could decide ammunition is a hazardous material and refuse to carry it at all. This hasn't 'happened yet, but the new IPSC rules are designed to make it possible for a competitor to buy factory ammunition at a match that would meet the power factor requirements.

Although Alexakos didn't exactly say it in so many words, being able to use factory ammo is also a safety issue. Some of the .38 Super loads make the 36,500 psi SAAMI pressure limit for the .38 Super as big a joke as putting a 55 mph speed limit on an interstate highway.

New Bullet Designs

Alexakos believes that IPSC needs to become more concerned with the real uses of handguns, rather than with gamesmanship. "There is no reason to push velocity anymore since bullet designs are so much better," he observed, referring to the new generation of self-defense ammo like the Federal HydraShok and Winchester STX. Ammunition available today represents a quantum leap over the loads from the '70s when IPSC's power factor rules were evolved.

However, it is significant to note that IPSC conducted no actual tests of currently available self-defense ammunition before arriving at the new power factors. The numbers were arrived at "by committee," quite literally. Here are the new IPSC classes and power factors:

Open: 160 major, 125 minor.

Standard: Pistol must fit within a box just slightly larger than what would be required for a standard 1911 pistol without optics or comps; 170 major, 125 minor.

Production: Duty pistols of 9mm or larger caliber. The gun must be DA or DAO. Single stage triggers are not permitted and the trigger must pull 5 lb. or more; 125 major, no minor scoring.

Revolver: No optics or comps permitted; 170 major, 125 minor.