Pf?

[shootemups]

Hey all,

How does one arrive at figuring the "pf" for the load?

I have a Chrony on order but have never used, nor know of how to figure the pf using such a machine..

This noob really appreciates any help!

[JMcDonough]

bullet weight times velocity such as 165gr bullet x 1000= 165 pf

[Sarge]

FPS X bullet weight 1050 FPS X 124 = 130200 Drop all but the first three digits

PF 130 Even if it comes out to 130999 it is still 130 PF

Weigh your bullets also. 124's are not always 124's if they are 124.9 then use that. If they are 123.5 then use that.. The Chrono stage will do it that way at a major match so no need surprising yourself.

[Corey]

as others have said with a slight addition: bullet wieght X velocity then divide by 1000 to drop the unnecessary digits. remaining 3 is your PF.

[shootemups]

Dang it! You guys Rock!

Thank you!

[shepheard]

What would minor and major be for a 45 with a 200 and 230. What about a 40 using 165 and 180. I have seen pf referenced in spring weights, like 160 to 180 etc. I want to load some lead and have heard that some bullets are designed for major or target loads. Not sure what the velocity range would be.

[HS101]

Click HERE It is a power Factor calculator. It's great and does the calculations for youB)

[shootemups]

Thanks guys.. Ok so after doing some reading and chart sniffing I have another question..

I see that a 180 grain hornady XTP needs 5.9grains of accurate N0.5 to start with a velocity of 849fps.

(would this be called the minor PF load?) @152PF

I see that a 180 grain hornady XTP needs 6.6grains of accurate N0.5 to MAX with a velocity of 965fps.

(would this be called the Major PF load?) @173PF

If my understanding is correct here, the "PF" is simply stating the "SUM" of results of information calculated and used , as it relates to the specific load data. IS there a reason to "sum" it up?

THanks! Told ya Im a NooB!

[Corey]

165 PF is the major cutoff. anything above 165 when doing the "weight x velocity / 1000" will be major. in your examples, the max load will comfortably make major, some testing would show you could go down a couple .1gr and still probably be ok.

ETA and yes, the starint load would be minor.

think of it this way:

PF always needs to be above 125. anything 125-164 is minor. anything 165 and higher is major.

Edited February 18, 2010 by Corey