sheepdog69 Posted May 31, 2017 Share Posted May 31, 2017 can any one tell me the necessary gear to compute power factor? what tools and techniques do you use? i shoot 9 mm but being pushed to shoot 40. looking for a limited pistol but considering an open any advice is appreciated Link to comment Share on other sites More sharing options...
superdude Posted May 31, 2017 Share Posted May 31, 2017 you need a chronograph to measure bullet velocity. once you have that, it's bullet weight times velocity divided by 1000. Link to comment Share on other sites More sharing options...
Guy Neill Posted May 31, 2017 Share Posted May 31, 2017 Power factor is the bullet weight, in grains, times the velocity, in fps, divided by 1000. As I recall, in Limited, to qualify for Major, it must be at minimum 40 caliber. You can use 9mm, but it will score as Minor no matter the actual power factor. Equipment would be a scale to weigh bullets, a chronograph to measure velocity and a calculator to do the calculation. Some chronographs will do the calculation for you Guy Link to comment Share on other sites More sharing options...
Dr Mitch Posted May 31, 2017 Share Posted May 31, 2017 You have got to get, or borrow, or tag along to use, a chronograph. It is a must. Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted May 31, 2017 Share Posted May 31, 2017 8 hours ago, sheepdog69 said: I shoot 9 mm .... but being pushed to shoot 40..... looking for a limited pistol.... but considering an open? As long as you're undecided, I would stick with the 9mm. Not sure what you mean "being pushed to shoot .40", BUT I wouldn't cave in ... stick with the 9mm. I definitely would NOT buy a Limited gun if you're considering Open ... Or, you'll end up with three pistols. Sounds like this might be a new hobby for you - I'd go slowly before investing a whole lot of money in it. For $70 - $100, you can buy a Chronograph - that will very easily tell you how fast your bullets are going. As Guy mentioned above, I'd fire 20 rounds over the chrono, make sure they all are at PF, and average the 20 of them. Weigh a bullet (many times 147 gr bullets are NOT 147.0 gr, but lighter or heavier). Multiply velocity (average) x bullet weight ( 148.5) and that number will be somewhere around 130,000, or so for 9mm Minor. Drop the last three digits, and it becomes 130 - that means your PF is 130, and you need 125 to make Minor PF minimum (drop below 125 PF and you are NOT shooting for score. Take your time, no reason to rush into .40 or Open - just enjoy and learn (or vice versa). Link to comment Share on other sites More sharing options...
jwhittin Posted August 18, 2017 Share Posted August 18, 2017 Don't waste your ammo. See this post for a simple and proven method to meet power factor. Shoot with any questions. Link to comment Share on other sites More sharing options...
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