Im losing sleep because of this!!!

[bigedp51]

Imr 4064 is temp sensitive. I believe 1 fps per degree change on average (from what I remember) back the charge off .2 grains and see what it does

The ammunition below was temp sensitive and loaded with RL15

Cartridge, Caliber 7.62mm, NATO, Ball, Special, M118LR (United States): 175-grain (11.3 g) 7.62×51mm NATO Match-grade round specifically designed for long-range sniping. It uses a 175-grain (11.3 g) Sierra Match King Hollow Point Boat Tail bullet. Produced at Lake City Army Ammunition Plant. The propellant's noticeable muzzle flash and temperature sensitivity led to the development of the MK 316 MOD 0 for Special Operations use.

The military switched to IMR-4064 a single base powder that is far less temp sensitive.

Cartridge, Caliber 7.62mm Special Ball, Long Range, MK 316 MOD 0 (United States): A 175-grain (11.3 g) round specifically designed for long-range sniping consisting of Sierra MatchKing Hollow Point Boat Tail projectiles, Federal Cartridge Company match cartridge cases and Gold Medal Match primers. The Propellant has been verified as IMR 4064 (per NSN 1305-01-567-6944 and Federal Cartridge Company Contract/Order Number N0016408DJN28 and has a charge weight per the specs of 41.745-grain (2.7 g)

Below double base powders are considered temp sensitive and the military selected IMR-4064 a single base powder.

[foxx]

The ammunition below was temp sensitive and loaded with RL15

Cartridge, Caliber 7.62mm, NATO, Ball, Special, M118LR (United States): 175-grain (11.3 g) 7.62×51mm NATO Match-grade round specifically designed for long-range sniping. It uses a 175-grain (11.3 g) Sierra Match King Hollow Point Boat Tail bullet. Produced at Lake City Army Ammunition Plant. The propellant's noticeable muzzle flash and temperature sensitivity led to the development of the MK 316 MOD 0 for Special Operations use.

The military switched to IMR-4064 a single base powder that is far less temp sensitive.

Cartridge, Caliber 7.62mm Special Ball, Long Range, MK 316 MOD 0 (United States): A 175-grain (11.3 g) round specifically designed for long-range sniping consisting of Sierra MatchKing Hollow Point Boat Tail projectiles, Federal Cartridge Company match cartridge cases and Gold Medal Match primers. The Propellant has been verified as IMR 4064 (per NSN 1305-01-567-6944 and Federal Cartridge Company Contract/Order Number N0016408DJN28 and has a charge weight per the specs of 41.745-grain (2.7 g)

Below double base powders are considered temp sensitive and the military selected IMR-4064 a single base powder.

I don't know this for a fact, only repeating what I think I remember reading from credible sources... some powders are very INsensitive to temp change in CERTAIN cartridges, Change the bullet, or caliber, etc. and it's insensitivity is lost. Similarly, a very sensitive powder in one particular cartridge can be made almost INsensitive in a different application.

[bigedp51]

I don't know this for a fact, only repeating what I think I remember reading from credible sources... some powders are very INsensitive to temp change in CERTAIN cartridges, Change the bullet, or caliber, etc. and it's insensitivity is lost. Similarly, a very sensitive powder in one particular cartridge can be made almost INsensitive in a different application.

Powder temp sensitivity listed on chart above, temp stability is represented in fps/per degree Fahrenheit.

Example, RL15 1.52 fps per degree of temp change and IMR-4064 0.45 fps per degree of temp change. Single base powders are not considered as temp sensitive as double base powder due to nitroglycerin content and are more temp sensitive.