Howdy cowboys and cowgirls.  For your safety and enjoyment, the MCP officers would like to share some information with you about “Power Factor” in your hand-loads.  Please read this article carefully.  Its purpose is to ensure our MCP members’ safety.  Note: This article only applies to smokeless powder loads.

Power Factor Definition

The Cowboy Action Shooting Power Factor definition from the Glossary of the SASS Cowboy Action Shooting Shooter’s Handbook Version 27.5:

Power factor – Bullet weight (in grains) times the velocity (in feet per second); divided by 1000. The minimum standard in all SASS matches for smokeless categories is not less than 60 and no velocity less than 400 fps. Maximum velocity for revolvers is 1000 fps. Maximum velocity for rifles is 1400 fps.

The Wild Bunch Action Shooting Power Factor definition from the Glossary of the Wild Bunch Action Shooting Shooter’s Handbook:

Power Factor – Bullet weight (in grains) times the velocity (in feet per second) divided by 1000. The minimum standard in all Wild Bunch™ Action Shooting matches is not less than 150. Maximum velocity for pistols is 1000 fps. Maximum velocity for rifles is 1400 fps.

SASS Rules Regarding Power Factor

Below is additional information regarding Power Factor, from the SASS Cowboy Action Shooting Shooter’s Handbook Version 27.5. An ellipsis ( … ) indicates omitted text that is not pertinent to this article. For more complete information, click the SASS Handbook link above.

Pg 23:

FAILURE TO ENGAGE/SPIRIT OF THE GAME A Failure to Engage or a Spirit of the Game infraction carries a 30 second penalty.  The accumulation of two Failure to Engage/Spirit of the Game penalties in the same match results in a Match Disqualification Penalty.  … Shooting ammunition that does not meet the power factor or minimum velocity.  The penalty is applied for each stage a competitor is checked and their ammunition is found to not meet the power factor or minimum velocity (Spirit of the Game).  …

Pg 25:

Power Factors The minimum standard for center-fire ammunition used in all smokeless categories in all SASS matches, including State, Regional, National, International, and World Championship competitions is not less than a minimum power factor of 60 and no velocity may be less than 400 fps. …  … Power factors can be calculated by multiplying the bullet weight (in grains) x the velocity (in feet per second) and then the resulting number divided by 1000.  Examples: 100 gr bullet traveling at 600 fps has a power factor of 60: (100×600)/1000=60.00 77 gr bullet traveling at 800 fps has a power factor of 61.6: (77×800)/1000=61.6 200 gr bullet traveling at 400 fps has a power factor of 80: (200×400)/1000=80.00 Power Factor / Blackpowder Smoke – Testing A Range Master, Match RO, or Match Director may, at their sole discretion, require the testing of any ammunition suspected of not meeting SASS ammunition specifications at any time during the match.  If a competitor’s smokeless ammunition is being checked for power factor, they will be asked to provide five rounds from each suspect firearm, already loaded at the loading table.  From the five rounds, one round will have the bullet pulled and weighed.  The other four rounds will be fired across a chronograph using the competitor’s firearm to record velocity data.  The muzzle should be raised to at least 80 degrees into the vertical before each shot is fired.  The competitor may not choose the firearm to be tested, all firearms regardless of caliber are subject to testing at any time. If the average velocity of the four rounds meets or exceeds the calculated power factor of 60 AND the minimum velocity of 400 fps, the loads will be considered legal.  If the loads do not meet the 60 power factor OR the minimum velocity of 400 fps, the competitor will be assessed a 30 second Spirit of the Game (SOG) penalty for the last stage completed.  Any subsequent stages completed with the illegal ammunition will result in the SOG penalty being assessed for those stages.  Two SOG penalties will result in a Match DQ. …

Why Is Power Factor Important to You and Our Club?

Jammed Cylinder

Too little charge can result in the primer backing out of the primer pocket when fired.  A backed-out primer can (and usually does) prevent the revolver’s cylinder from rotating to the next position.  On the other hand, a sufficient charge slams the base of the brass casing against the frame’s recoil shield hard enough that the primer cannot back out of the primer pocket.  Below is a photo of a backed-out primer that bit me.  Put a fired piece of brass in one of your revolvers and then, using an automotive feeler gauge, measure the head space (the space between the brass and the frame.  It doesn’t take much to jam a cylinder with a “proud” primer. 

Squibs

Too little charge can result in a squib.  That is, a round that goes off but the cast lead bullet does not leave the barrel.  The pistols and rifles that we use in Cowboy Action shooting have rifling grooves in their barrel.  The cast lead bullet is intentionally sized to be bigger than the inside diameter of the barrel (the ridges called lands).  This rifling design imparts a spin on the bullet, keeping it stable in flight.  When a round is fired, the sudden pressure must be enough to enable the cast lead bullet to escape the brass case and be forced out of the barrel despite the drag of the barrel’s lands.

So, please be safe and keep your hand-loads charged to at least the powder manufacturer’s “Starting Load” for the caliber and cast bullet that you’re using. 

And check your ammo’s Power Factor.  If you need help checking power factor, just ask one of the MCP officers.  We can connect you with a member who has the necessary time, knowledge and equipment.  Really!  Seriously!  Our club has members who are more than happy to help. 

Our club is a SASS-affiliated club that abides by the SASS Cowboy Action match rules.  Using ammo that does not meet the Power Factor requirement is not only SASS-illegal, it’s also dangerous to you and others.  Let’s all be safe while we enjoy our Cowboy Action shooting hobby.