Heat, sweat, primers and ccw

Here's what I tell my CCW students here in sunny S. AZ:

Modern centerfire ammunition can be stored almost indefinitely, as long as it is kept in a cool, dry place. High heat(as in 120+degrees in a parked car in the summer) degrades smokeless powder over time; humidity(as in body sweat and water vapor) can seep into cartridge case mouths and primer pockets that are not sealed and contaminate powder and primers over time.

Change out your old carry ammo for fresh carry ammo at least once a year. If you are genuinely carrying the gun concealed on your person every day, day in/day out, make that every six months if you can. Take the old ammo you've sweated on and kept in your hot car for the past 6-12 months to the range and test-fire it. If it fires without any problems, your fresh ammo should be good to go for the next 6-12 months. If you get any misfires, buy fresh carry ammo and rotate more frequently.

Face it - you're literally betting your life on this ammunition - if the $25-50 you have to pay for a fresh box of JHP's twice a year is too much for you, please reconsider your budgetary priorities...

I leave loaded guns in my cars for years in the hot Texas sun. Never had the slightest sign of a problem with the ammo, and don't expect any.

Ammo is water tight, of course there's always an exception.

In short, IMO there's no problem., except keeping the sweat from rusting the gun.

If it makes you feel better, change out your ammo once a year or more often. In any case it doesn't hurt to run your carry ammo through the gun once in a while, so shoot it and load fresh.

The sweat will hurt the gun more than the ammo... Good carry ammo has sealant around the primers anyway.

That is part of the reason I carry a Glock; between the polymer and tennifer, there is really just about zero environmental condition it won't shrug right off. Prior to that I was carrying Sigs, and didn't like sweating on those "nicer" pistols, especially the 228 with the blued slide. That was rust waiting to happen. The nitron is better, but I still don't think it is as good as tennifer.

I worked mostly outdoors in Houston for one summer about 3 years ago (worst heat and humidity especially, that I have ever encountered anywhere), and had switched to the G19 and Comptac holsters by that time, and it was fine. Got a little bit of rust on some of the hardware on the holster, but it could be wiped off and didn't affect function. The belt, on the other hand (Beltman leather)... it was soaked through every day and basically ruined within that 3 month stretch. Got a Wilderness Instructor's with stiffener after that; it is still going strong. Based on all this, for carry gear, make mine with as much polymer and synthetic material as possible; thanks.

Ammo, being contained within the gun or mag, should not be directly subject to liquid sweat, but it is pretty durable anyway. I rotate mine every 6 months to a year or so and consider that schedule to be more than enough. I'm more worried about setback from repeated chamberings than I am about powder degradation from environmental conditions.