45LC Hunting Load Evolution

[Arktikos]

On top of all the other variables like the components of bullets (type and sizing) primers, powder lot, and the differences in gun barrels, both length, chamber diameter and bore, there are the external variables like outside temp (which affects both air density and burn rate of the powder), elevation above sea level and probably lots more. I think most of the times all these variables work to partially cancel each other out, but sometimes can work to stack on each other too.

[Model 52]

On top of all the other variables like the components of bullets (type and sizing) primers, powder lot, and the differences in gun barrels, both length, chamber diameter and bore, there are the external variables like outside temp (which affects both air density and burn rate of the powder), elevation above sea level and probably lots more. I think most of the times all these variables work to partially cancel each other out, but sometimes can work to stack on each other too.

Altitude actually has comparatively little effect on air density, speed of sound, mach number and drag coefficients. Temperature is the prime mover here.

It's a double hit as colder ammo usually produces lower velocity at the same time that the bullet experiences increased air density, increasing drag and presenting greater stability challenges to the slower moving and slower spinning bullet.

[Arktikos]

On top of all the other variables like the components of bullets (type and sizing) primers, powder lot, and the differences in gun barrels, both length, chamber diameter and bore, there are the external variables like outside temp (which affects both air density and burn rate of the powder), elevation above sea level and probably lots more. I think most of the times all these variables work to partially cancel each other out, but sometimes can work to stack on each other too.

Altitude actually has comparatively little effect on air density, speed of sound, mach number and drag coefficients. Temperature is the prime mover here.

It's a double hit as colder ammo usually produces lower velocity at the same time that the bullet experiences increased air density, increasing drag and presenting greater stability challenges to the slower moving and slower spinning bullet.

Yes, agreed, but if Paco was measuring his speed up in the Rockies at 9000 feet it would have some difference over me here at sea level.. My main point was that difference in variables between the OP's gun, components and environment over Paco's could, if not canceling themselves explain at least some of the OP's question.