Every type of powder may have different temperature sensitivity and some are more sensitive to temperature change than others. The muzzle velocity can vary noticeably especially considering a temperature change such as from 20 F degrees in the winder to 95 F degrees in the summer.
If you developed a maximum load in a 20 F degrees winter condition using a temperature sensitive powder, is it true that it may be too hot a load (therefore it may be unsafe) for 95 F degrees summer condition? Even for loads that you think are safe, the velocity can vary a lot and therefore the grouping/accuracy may change such that the best load data developed in winder may not be a good data for summer conditions.
I had compared two of my tests of .223 rem. A 22 F degrees drop (from 42 F to 20 F) resulted in a 155fps drop in muzzle velocity. This is 23gr IMR 4895 with 55 gr FMJ from a 1/12 twist rate Rem 700 SPS 26” .223 rem rifle. The 155fps drop seems too much to believe but that was what I got.
I am curious how you guys modify your load data over different seasons (temperature conditions).
Thank you in advance for any info.
If you developed a maximum load in a 20 F degrees winter condition using a temperature sensitive powder, is it true that it may be too hot a load (therefore it may be unsafe) for 95 F degrees summer condition? Even for loads that you think are safe, the velocity can vary a lot and therefore the grouping/accuracy may change such that the best load data developed in winder may not be a good data for summer conditions.
I had compared two of my tests of .223 rem. A 22 F degrees drop (from 42 F to 20 F) resulted in a 155fps drop in muzzle velocity. This is 23gr IMR 4895 with 55 gr FMJ from a 1/12 twist rate Rem 700 SPS 26” .223 rem rifle. The 155fps drop seems too much to believe but that was what I got.
I am curious how you guys modify your load data over different seasons (temperature conditions).
Thank you in advance for any info.
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