Lefty Wheeler Posted March 13, 2011 Share Posted March 13, 2011 With a chronograph measuring the speed is there a formula to determining the power factor with the lead grain. The following is refered from the Shooter Handbook. 34. The minimum standard for center-fire ammunition used in all smokeless categories at 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. The maximum velocity standard for revolvers is 1000 fps. The maximum velocity standard for rifles is 1400 fps. Buckaroo Category shooters choosing to use center-fire ammunition in handguns and/or rifles must also meet all power factor and velocity requirements. Pocket pistols and derringers are exempt from the power factor and velocity requirements. Thanks for any information Lefty Wheeler Link to comment Share on other sites More sharing options...
Captain Woodrow Cahill, SASS # 54363 Posted March 13, 2011 Share Posted March 13, 2011 Power Factor is calculated by taking the speed of the bullet in feet-per-second and mutliplying that by the weight of the bullet in grains, then dividing that number by 1,000. I think the IDPA came up with this formula for their various competition categories. Link to comment Share on other sites More sharing options...
Badlands Bob #61228 Posted March 13, 2011 Share Posted March 13, 2011 For example: 125 grain bullet at 800 feet per second 125 x 800 = 100,000 100,000 \ 1,000 = 100 power factor Link to comment Share on other sites More sharing options...
Lefty Wheeler Posted March 13, 2011 Author Share Posted March 13, 2011 A big thanks LW Link to comment Share on other sites More sharing options...
Levi Astorbilt Posted March 13, 2011 Share Posted March 13, 2011 Lefty, a power factor of 60 is extremely slow/low. A velocity slower than the 400 fps minimum for any given bullet. You can reach that using a 250 gr 45 bullet and a slingshot. 250 gr X 240fps. = 60,000 / 100 = PF of 60 Link to comment Share on other sites More sharing options...
PaleWolf Brunelle, #2495L Posted March 13, 2011 Share Posted March 13, 2011 Howdy Lefty, It can also be found in the back of the RO1: 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. RO1 "Glossary of Terms" p.31 Link to comment Share on other sites More sharing options...
Dubious Don #56333 Posted March 13, 2011 Share Posted March 13, 2011 The exact testing procedure can be found on page 14 of the RO II manual. It is the average of four rounds and most importantly, raising the barrel to 80 degrees for each shot DOES make a difference! Link to comment Share on other sites More sharing options...
Adirondack Jack, SASS #53440 Posted March 13, 2011 Share Posted March 13, 2011 Lefty, a power factor of 60 is extremely slow/low. A velocity slower than the 400 fps minimum for any given bullet. You can reach that using a 250 gr 45 bullet and a slingshot. 250 gr X 240fps. = 60,000 / 100 = PF of 60 Think about it. If a 250 grainer reaches a 60 PF at 240 fps (illegal as it is below 400 fps), and a 125 grainer reaches a 60 pf at 480 fps (legal), a bullet of 80 grains reaches a 60 PF at 750 fps,(legal) and a 60 grainer has to be doing 1000 fps (illegal in a handgun for running too fast). It ain't all about velocity, but is equally about bullet WEIGHT. Link to comment Share on other sites More sharing options...
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