gary2232 Posted May 1, 2012 Share Posted May 1, 2012 (edited) Sorry about the typo in subject line I ment to say Power Factor What can expect if I chrono my loads at say 70 degrees and adjust as needed to make 125 PF. Then I test again at say 100 degree temp. Will I gain or lose fps? I live and test in a hot valley town and. Shoot some matches in the cool bay area. I do not have enough experience Reloading to know what to expect so I can adjust or give myself enough cushion for the temp variance. thanks Edited May 1, 2012 by gary2232 Link to comment Share on other sites More sharing options...
superdude Posted May 1, 2012 Share Posted May 1, 2012 some gunpowders are temperature sensitive and some are not. what load are you using? perhaps someone with experience with that gunpowder will be able to answer your question. Link to comment Share on other sites More sharing options...
dover0020 Posted May 1, 2012 Share Posted May 1, 2012 We need to know what powder you are loading with. Link to comment Share on other sites More sharing options...
Sarge Posted May 1, 2012 Share Posted May 1, 2012 And, some powders are reverse temp sensitive. i.e they weaken when it gets hot and strengthen when it gets cold. Most are generally not so sensitive either way to cause problems at chrono but some are. This is why I ,if at all possible, settle on powders that are not prone to changing much if any with temperature changes. Powders that I know of: Any V V powder is very stable. WAC is pretty syable TG is temp sensitive(velocity goes up with heat) S1k is reverse(velocity goes down with heat) There are others and I'm sure folks will check in and let you know. FWIW, there is nothing like KNOWING what your load is going to chrono at no matter where/when you shoot it. Link to comment Share on other sites More sharing options...
Alan550 Posted May 1, 2012 Share Posted May 1, 2012 WST is also reverse sensitive, i.e. the higher the temp, the slower the velocity. Alan~^~ Link to comment Share on other sites More sharing options...
gary2232 Posted May 1, 2012 Author Share Posted May 1, 2012 Ok sorry for the lack of info. I should have included My powder info. I am using Winchester 231 3.8gr and Bear Creek 135gr bullets. I did not think that different powders would react oppositely. Thanks. Link to comment Share on other sites More sharing options...
superdude Posted May 1, 2012 Share Posted May 1, 2012 i don't think 231 has a reputation for being dramatically temperature sensitive like some other gunpowders. Most competitors will load with a margin of error. for example, for a 125 power factor they will load to 130-135 power factor. this allows for changes in temperature and also differences in chronographs. even gunpowders with reputations for being temperature stable can show slight but measurable changes in velocity due to temperature, so loading with a margin of safety is always a good idea. Link to comment Share on other sites More sharing options...
gary2232 Posted May 1, 2012 Author Share Posted May 1, 2012 Ok sounds good I am at 130PF now so I should be good. Thanks for The replys all Link to comment Share on other sites More sharing options...
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