temp affects of powder

[pwdrbrn]

anyone know the temp affects of h-1000,869,varget ,r-19,25,4831sc? the list goes on ,but i am loading in 50-60 deg shooting at 90-100+ if so to these any suggestions to altering load's? thank's

[22popnsplat]

the temp when you load them I dont belive has any affect on the outcome , many powders are temp sensitive as to when there fired . the same Loads that are safe to be fired at 50 degrees may develop more pressure when fired at 100 degrees .

[sargenv]

Hodgdon has what they call their "extreme" line of powders.. these powders are not temperature sensitive.. ie they fire ther same regardless of the temperature conditions.. other powders can be reverse sensitive, meaning that pressure goes up when they get exposed to colder temps.. and then there are the usual powders that increase pressure as temperature rises. It might be best to contact the powder manufacturer on something specific..

[rsrocket1]

+1 to what popnsplat says. The powder does not expand or contract measurably at those differences in temperature, besides you are setting your charges by weight at the start of each loading session (aren't you?). Weight is what translates into the energy content of the powder so 25g of Varget at 50F is 25g of Varget at 100F.

If you are near maximum pressures or loads, be very careful on hot days because some powders (especially ball powders) can vary a large amount when the temperature changes. I ran some unscientific experiments last winter where I took 223's loaded with H335 and the difference between rounds that were cold soaked at 40F overnight shot about 30-50fps slower than rounds that warmed up to 80F in my car on the drive to the range (half an hour with the heater blowing on the ammo).

Stick powders in general are less sensitive to temperature changes than ball powder and Hodgdon advertises Varget as extremely stable across the temperature scale.

[pwdrbrn]

rsrocket1- as far as setting cartridges in order of load always it's just a way of practice. this question was solely put out for extra info ,hatcher's notebook touched on it a little but,things have changed since then,the extremes that i experience while i load i must take into account, eg: load the same charge 5 times,chrono each load at different temps and record,thank you for the reply,a little input from others help's alot

[pwdrbrn]

22popnsplat-interesting,just wondering if there was a rule of thumb for loading cool and firing hot eg:60deg-shooting 100+thanks for reply