Day 3 test, ammo left outside overnight in temps of -25C (-13F) . Was exactly -19C (-2F) when I shot, same as day before with cold gun/cold ammo.. Rifles were left inside all night, loaded into warm truck (heater set to 22C / 72F) and left inside the idling truck until ready to shoot.
Ruger Scout 223, 55gr Hornady SP / IMR 4198
Cold gun - 2871 fps
Warm gun - 2881 fps
Tikka T3x CTR 6.5 Creed
130gr Sierra TGK / RL17
Cold gun - 2817 fps
Warm gun - 2819 fps
147gr ELDm / RL26
cold gun - 2533 fps
warm gun - 2561 fps
Tikka 6.5 PRC
140gr Nosler Accubond / RL26
cold gun - 3075 fps
Warm gun - 3071 fps
143gr Hornady ELDx / RL26
cold gun - 2925 fps
warm gun - 2909 fps
Defiance 280 Ackley
160gr Nosler Accubond / RL26
cold gun - 3001 fps
warm gun - 3010 fps
165gr Sierra TGK / Accurate MagPro
cold gun - 2800 fps
warm gun - 2814 fps
195gr Berger EOL / RL26
cold gun 2677 fps
warm gun 2671 fps
Ruger m77 Scout 308 Win, 208gr ELD / Varget
cold gun - 2215 fps
warm gun - 2241 fps
Ruger no1 300wm 175gr LRX / RL26
cold gun - 3067 fps
warm gun - 3063 fps
Defiance 338-06
230gr ELDx / Ramshot BigGame
cold gun - 2489 fps
Warm gun - 2515 fps
250gr Woodleigh PP / Ramshot BigGame
cold gun - 2389 fps
warm gun - 2399 fps
Ruger m77 375 Ruger
270gr LRX / Ramshot BigGame
cold gun - 2578 fps
warm gun - 2579 fps
300gr Nosler Parition / Win760
cold gun - 2550 fps
warm gun - 2556 fps
Average speed of cold rifle = 2713 fps
Average speed of warm rifle = 2720 fps
.003% change. I think it's safe to say the temperate of the rifle plays a very minimal role in velocity of the ammunition.
