Jump to content
Brian Enos's Forums... Maku mozo!

calculating power factor


Recommended Posts

  • 5 months later...

Congrats on getting a chrono! :cheers:

In my book it is as important for reloading as a powder scale or digital//dial/vernier caliper.

If you are shooting USPSA might want to look at the rule book for the definition (section 5.6) and actual chrono procedure/power factor calculation (appendix C2) so you you can understand what you need to meet at a match and adjust your loads accordingly.

http://www.uspsa.org/rules/2010HandgunRulesProof3web.pdf

Link to comment
Share on other sites

Congrats on getting a chrono! :cheers:

In my book it is as important for reloading as a powder scale or digital//dial/vernier caliper.

If you are shooting USPSA might want to look at the rule book for the definition (section 5.6) and actual chrono procedure/power factor calculation (appendix C2) so you you can understand what you need to meet at a match and adjust your loads accordingly.

http://www.uspsa.org/rules/2010HandgunRulesProof3web.pdf

+1

Link to comment
Share on other sites

whats the method for calculating POWER FACTOR ?

If you're shooting a 125 grain bullet at 1,000 fps, your PF is 125.

But for competition purposes, you'll find that firing 20 rounds over

your new chrono will yield a variation (950 - 1,050 fps, eg).

So, you should use the lowest velocity x bullet weight to come up

with a 118.75 PF, and bump up your powder charge a bit so that

the LOWEST velocity you get is a PF 125.

:cheers:

Link to comment
Share on other sites

  • 3 months later...

I realize this an older thread but thought I would share my opinion with Hi Power Jack anyway. I try to load all my rounds at 130 PF, That way, if you ever have your rounds chrono'd at a match, your avg velocity should be good to go. This should also make you safe from temperature variances from the day you tested your loads and having them tested at a match.

Link to comment
Share on other sites

I load my rounds at 130 PF, your avg velocity should be good to go & make you safe from temperature variances

Level, we're really saying the same thing. If you check 20 of your PF 130 rounds, you'll probably note that NONE of the rounds

is below PF 125. But, some are pretty close to 125.

And, if you check to see if NONE are below PF 125, you'll probably have a PF of c. 130.

But, depending on your powder, PF130 may NOT make you immune to severe temp variances - you might need greater PF.

Link to comment
Share on other sites

I load my rounds at 130 PF, your avg velocity should be good to go & make you safe from temperature variances

Level, we're really saying the same thing. If you check 20 of your PF 130 rounds, you'll probably note that NONE of the rounds

is below PF 125. But, some are pretty close to 125.

And, if you check to see if NONE are below PF 125, you'll probably have a PF of c. 130.

But, depending on your powder, PF130 may NOT make you immune to severe temp variances - you might need greater PF.

Hence the importance of owning or at least having unfettered access to a chrono to be able to test loads in a myriad of conditions if one is competing regularly.

Link to comment
Share on other sites

If you want to check your margin of safety with your power factor, you can check out my spreadsheet posted in the thread called what's your power factor margin of error.

Sorry- not allowed to post

the link

Edited by CZinZA
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...