I always keep a spare loaded mag in the car. What can this possibly do to powder/primers? Any possible negative effects?
No negative effects. Just keep ammo dry and that includes condensation from radical temp environment changes.
I have 18 357 rounds and 8 44 mag rounds in the car now. -12 this am we will see what happens when I fire them off next range trip.
j**N, You KNOW that they will shoot just fine...Bill
Yep, I'd think condensation from temp changes would be the enemy, but I've never really left any in the car to test, and definitely not for an extended period. Not sure if condensation that would refreeze potentially could potentially cause some issues with feeding, or reliability.
For the OP, I'd make an effort to cycle that ammo during range trips, but that's me.
Somewhere a Soviet WWII vet is laughing at this thread.
Just a statement but you guys do know that ammunition is transported in semi trucks with all the other freight. Depending on the distribution center distance and how long it takes for employees to get it unloaded it may sit in the heat or cold for a while. I would assume this happens multiple times in the distribution chain before it hits the shelves unless its hand loaded. If it wasnt a problem for all the other rounds you can bet it wont be bad for yours.