Power factor is designed to help keep the playing field equal in USPSA divisions around ammunition performance and firearm recoil. The Power factor calculation is an effective way to measure ammunition’s relative performance from a competitor’s firearm and group them into Major and Minor categories.
Recoil Effects
When your pistol generates lower recoil or muzzle flip, your ability to take accurate follow-up shots and shoot faster on targets is increased. When you have heavier recoil, your ability to shoot quickly with follow-up shots is reduced, as the gun can be more challenging to control.
Power Factor Rating
Minor power factor will have a rating of 125 to 164, and major is 165 or higher. Larger calibers and cartridges are more commonly used to make major power factor because they support larger powder loads. Smaller centerfire cartridges, like 9mm, are more common in minor.
Calculating Power Factor
The power factor calculation uses your bullet’s weight in grains, multiplies that by the velocity in feet per second, then divides it by 1,000. For example:
[Bullet Weight (Grains) x Velocity (Feet Per Second)] / 1,000 = Power Factor (PF)
• Minor PF = 125 to 164
• Major PF = 165 or greater
Minor Power Factor Example:
• 9mm 124 GR bullet traveling at 1,009 Feet Per Second (FPS).
• Multiply 124 by 1,009 and then divide by 1,000, and you get 125.116.
• Minor 125 PF = (124 GR x 1009 FPS) / 1,000.
Major Power Factor Example:
• .40 S&W 180 GR bullet traveling at 917 FPS.
• Multiply 180 by 917 and then divide by 1,000, and you get 165.06.
• Major 165 PF = (180 GR x 917 FPS) / 1,000.
Note: in USPSA competition, any ammunition and pistol combination that does not perform at or above the minor 125 PF floor cannot receive a stage or match score.
Major vs. Minor Scoring
When a firearm division supports major and minor power factor scoring, you will have a scoring advantage shooting major power factor. Higher points are awarded across the lower-scoring areas of paper targets. When you score one target, it does not seem like a significant advantage, but it makes a difference when added up over an entire stage of targets.
Ammunition performance affects how you score cardboard targets. Major power factor is awarded more points for less accurate hits on cardboard targets. This difference may not seem like much on a single target, until it is taken across an entire stage of multiple targets.
Major vs. Minor Hits
When shooting anything other than alphas, the differences in major and minor hit scoring start to appear. This example shows two hits: one alpha and one charlie. Depending on the power factor (PF), different points will be awarded.
Major will get five for the A and four for the C, for a total of nine points. Minor will get the same five for the A but will get only three points for the C, for a total of eight points.
If you are competing in a single power factor division, you won’t need to think about the differences in multiple power factor scoring. However, if you are shooting with minor power factor and your competitors are shooting major, it is essential to understand the examples below to play a competitive game.
When you shoot minor power factor in a USPSA division that supports major and minor, you must understand how the lower recoil contributes to your performance and if it is worth it. There is a progressive decrease in target scores as you move from all alphas to a mix of other scoring zones.
Major vs. Minor scoring and Divisions
For Open, Limited, Limited 10, Single Stack 1911, and Revolver divisions, you will collect higher points using major power factor ammunition. For divisions like Production and Carry Optics, everyone is scored using minor power factor only, so there is no advantage to shooting major.
Gary Hybridge 