Me and a friend were talkin about leaving our handguns in the truck. And he brought up the question is it better to leave it in so it stays the same tempeture. Or to carry them in the house when you get home, where the temp would change from like 50* outside to 75* inside. Now his argument was based on the gun rusting due to drastic change.

Never leave a gun in a vehicle. Especially when you are home. Helps prevent theft.

Some folks leave a gun in the car or truck all the time. While I agree it isn't as secure there it is done. I recall in the '60s when i worked in a gas station cleaning a car and finding a loaded Ruger Blackhawk. My brother keeps a derringer in his truck. Of course, you can forget it is there. I have heard many stories of folks going into Canada with a gun in their car or truck.

Some guns are very tolerant of humidity. The S&W M&P automatics have polymer grips and stainless slides.

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Luke 22:36

Have a lot of friends in Georgia that leave their shotguns in the truck during hunting season and they don't have a lot of trouble with rust. It does happen occasionally though so if it stays there be sure it is cleaned and oiled.

They don't have much trouble with theft as they live in very rural areas and don't have people walking by. When going to work they of course remove the gun as it's not allowed on the work property.