Is there a minimum FPS my ammo needs to chrono at?

[Newby]

I am new (hence the Newby name) to USPSA. I was told the minimum for any projectile is 750 fps, is this true?

I want to shoot single stack, and was planning on a 230 gr bullet...

[Loves2Shoot]

Not true,

Read the rule book and look for "power factor"

velocity * bullet weight / 1000

Using your example 717.5 * 230 / 1000 = 165

The minimum power factor for major is 165.

[a.roberts]

Not exactly.

In USPSA there's a "power factor".

Bullet weight in grains times velocity in feet-per-second divided by 1000.

125 is the minimum for Minor and 165+ is Major.

In Steel Challenge, 750fps is the slowest a bullet is allowed to go.

[sfinney]

Major Power Factor is 165, which is that your FPS must be over 165,000 divided by the weight of your bullet.

In your case 165,000 divied by 230 grains, which is 717.39 FPS to make major.

You can shoot minor shooting speeds under that FPS, or Power Factor, but to score at all even as Minor for a match the real minimum is 125 Power factor, or 125,000 divided by your grain weight of 230, = 543.47 FPS.

Major versus Minor affects your scoring, check out a USPSA rulebook for more info.

I have seen some local clubs enforce a different minimum FPS rule, and Steel matches in particular, (to avoid bullet bounce back off steel??) but that is not the USPSA rule.

Edited July 24, 2010 by sfinney

[Newby]

Major Power Factor is 165, which is that your FPS must be over 165,000 divided by the weight of your bullet.

In your case 165,000 divied by 230 grains, which is 717.39 FPS to make major.

You can shoot minor shooting speeds under that FPS, or Power Factor, but to score at all even as Minor for a match the real minimum is 125 Power factor, or 125,000 divided by your grain weight of 230, = 543.47 FPS.

Major versus Minor affects your scoring, check out a USPSA rulebook for more info.

I have seen some local clubs enforce a different minimum FPS rule, and Steel matches in particular, (to avoid bullet bounce back off steel??) but that is not the USPSA rule.

I came to the right place

Thank you for the rapid responses. The minimum for steel plate makes sense, and glad to hear it is ONLY power factor for uspsa.

[Joe4d]

The rule book is your friend, next time the infamous "They" tell you, say,"thats great thanks, What page is that on ?"

[LT45]

Here's a handy little chart I made a while back.

I've done all the math and rounded up.

Listed are a lot of the common bullet weights and speeds required to make major or minor power factor for pistol.

Hope this helps.

LT

[spanky]

That's a very helpful chart, LT. Thanks!

[Newby]

THanks for the chart

[Graham Smith]

The only thing other to keep in mind is that lower PFs may not cycle a stock gun properly. You may have to tune it with different springs to work.

[Field]

oh man the match i was at today was a chrono match and some dude went sub minor, oh what a poor sucker

[mpolans]

Major Power Factor is 165, which is that your FPS must be over 165,000 divided by the weight of your bullet.

In your case 165,000 divied by 230 grains, which is 717.39 FPS to make major.

You can shoot minor shooting speeds under that FPS, or Power Factor, but to score at all even as Minor for a match the real minimum is 125 Power factor, or 125,000 divided by your grain weight of 230, = 543.47 FPS.

Major versus Minor affects your scoring, check out a USPSA rulebook for more info.

I have seen some local clubs enforce a different minimum FPS rule, and Steel matches in particular, (to avoid bullet bounce back off steel??) but that is not the USPSA rule.

Keep in mind, once you get below a certain velocity, it gets real tough to hit bobbing, swinging and moving targets.

Which makes me wonder, at what point would increased bullet weight and decreased velocity result in a round that would be less likely to result in an ambulance trip and more likely to result in an "ouch" if one were shot with it? For example, hypothetically, one could shoot Revolver minor with a .500 S&W mag revolver. Using 700gr. LFPs and ignoring the rainbow trajectory, one would only have to push them 180fps...or about 122mph...slightly faster than a MLB fast ball. That seems much less lethal than a jai-alai ball (2,100gr. traveling at 275fps) or a golf ball (708.4gr. traveling at 220fps off a tee).

[Field]

For example, hypothetically, one could shoot Revolver minor with a .500 S&W mag revolver. Using 700gr. LFPs and ignoring the rainbow trajectory, one would only have to push them 180fps...or about 122mph...slightly faster than a MLB fast ball. That seems much less lethal than a jai-alai ball (2,100gr. traveling at 275fps) or a golf ball (708.4gr. traveling at 220fps off a tee).

yeah ive seen a few revo shooters shootin some loads and i was thinkin they were fudging that minimum pf thing a bit on the low side

[robin303]

Yes, Thanks for the chart LT45.