Why do people say to rotate carry ammo?

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Jan 5, 2003
The sunshine state,Florida
I've seen this said here and on TFL before my question is why? Is it due to chambering the same round over and over again? (which I never really do) or is it because of the moisture in the air over time can do something to the bullet's powder? I know these may seem like stupid question but if there is a reason why carry ammo should be changed then what is it? How often should you change out your carry ammo?

I know there has been ammo in storage for years that has gone bang so I am just wondering is all. One last note is I carry my S&W 640 alot in the summer if this matter as far as changing you carry ammo goes? Is it reccomended more in an auto? If so how often should I rotate my carry ammo in my guns? Thanks
It might have something to do with the bullets becoming seated more deeply in the case after numerous chamberings. Also, ammo that is carried every day is subjected to harsher environments than the cozy inside of an ammo can. This is a question for someone more knowledgeable than I, but those are my thoughts anyway :confused:
Not being an expert on this (or anything else:D )
I think the reason is "freshness".You wouldn't eat year old
breakfast cereal,why would you trust your life to questionable
ammunition?Nothing last forever.Neither does powder.
Now ammo does have a long shelf life,but why take chances.
I think LEO's change their ammo every 6 months,not sure.
Just my $.02.

Mega, to ensure reliability. Cartridges that are carried may become damaged via bullet setback, weather, perspiration, lubrication from the weapon, etc.

I have seen police ammo that was green. Rotate your ammo as you would change the oil in your car. I change it monthly. Ammo is like beer, better when fresher.:)
Even if there is no sign that your carry ammo is bad compared to your life it costs nothing. Use some for a month, put it away for practice and use some fresh stuff from the box. It can't hurt.
Cartridges that are carried may become damaged via bullet setback, weather, perspiration, lubrication from the weapon, etc.
I was going to mention the part about the chemicals in the lubes that we use in our guns. There is always the "possibility" that they can effect the ammo carried in them.

I can't cary here in IL, but I change the ammo out in my house gun every 4 months. Then shoot up the box at the end of the year and by fresh.
Might not be necessary, but it can't hurt.
Gun lubes and gun oils, particularly the penetrating types, will make primers worthless. Does bad things to smokeless powder, too.

Bullet setback spikes pressure in a hurry. People whose opinions I value have been suspecting bullet setback as the primary culprit in the .40 Glack ka-bangs for some time now.

None of my duty ammo is older than six months.

While I see no real reason for rotating ammo, it sure doesn't hurt. Call it insurance, if you will...

I have some GI steel-case EC 43 .45ACP which still goes Bang! every time. I have some .243 I reloaded in 1968, and while its point of impact is an inch or two below fresh stuff, it groups quite nicely. Same for some .220 Swift and some .22-250 of my father's, loaded in 1974. And some GI Carbine reloads...

I have various revolver reloads that are anywhere from ten to twenty years old; they always do as one would hope: Go Bang!

So I dunno. One thing about it, however; ammo's really cheap, compared to any ambulance ride or hospital stay...

I have heard of cases of overlubricating a gun, which then destroyes the primers. There have been police officers that have done this (among others, it is just the police reports I have heard) where they squeeze the trigger and it does not go BANG!

I know it's not realistic for everyone, but I never seem to keep ammunition around long enough to have to rotate my stock and what I keep in my carry weapons. My concept of 'rotating ammo' is to buy more.


My former roomie...

was in the Navy. Just before they came back into port, they'd burn up every round that was on the ship. If they didn't shoot it, it got dumped over. My understanding was that old ammo got corroded from the salt air.

Handle a fresh, shiny round a little and then set it on a shelf for a few months and see what it looks like. The case will be tarnished.

Reasons I can see are;

deterioration due to oils

corrosion from perspiration

set-back from chambering
I rotate my carry ammo every 4 to 6 months. For all the reasons put down already.

Its a peace of mind / insurance / confidence thing, and supplies me with factory ammo to test / evaluate.
Well, I recently rotated my dads double stack of 9mm...

He had been carrying it for 9 years.

Same bullets...for 9 years...:rolleyes: :uhoh: :eek:

The casings were so deformed from the spring tension and the constant motion of being worn all day, every day...I seriously doubt they would have even fed into the chamber.

And some of the casings were so creased I guarantee they would have split open.
I figure if I'm shooting my defensive ammo I'm actually practicing with what I'd carry. Thats the best reason to shoot it once in a while.
I rotate mine at least once a month during the summer. it has been approaching 100 here in South Texas , between sweating and keeping the gun lubricated so it won't rust I don't want to take a chance with ammo going bad.
On a related note...I always chamber the same round after unloading...otherwise I am always stripping the first round of the top of the mag and that one may deform and wind up back in the top mag position...best to remove that top round and chamber the same one, keeping your feed rounds pristine...
Usually guys who tell you that are not telling you the taxpayers are paying for it?

I don't chamber and unload rounds all the time. Those who have to might have a different answer, esp with a gun in 40 S&W or other high kB potential rounds. 38 Spl or other revo could remain loaded for decades and still be deadly as a snake, imho.
If you check my grid coordinates, you'll see that climate alone dictates regular ammo rotation. My department rotates ammo every 6 months coinciding with qualifications. Any pratice is conducted with our training ammo. Actual qualification is done with the old carry ammo. New carry ammo is issued to the officers as they complete quals.
If you carry or plan to protect yourself in emergencies with a handgun, you should be practicing regularly anyway. Since you practice, you should be trying out the actual defensive ammo that you plan on using.

Just this should explain why ammo is rotated, although the above also are good reasons.
I try to shoot my CCW magazine (the one that stays loaded with HPs) every month or so.

Helps me rotate the ammo, and make sure that the gun is still reliable with said ammo.
As arinvolvo said its a good idea to make sure your gun will still run with your fullhouse defensive ammo. Its probably also helpful if you use .38 a lot at the range to use the real stuff (.357) now and then. Also as someone mentioned earlier carry guns should have their ammo used periodically (not rotated, USED) to prevent case damage etc from the constant motion.

Ammo basically doesn't grow old and lubrication, i suspect is an urban myth. I remember seeing something from CCI that said if you sprayed their primers with WD40 they would still work fine after they had dried out. Also i suspect that unless your using something like Kroil it aint going to creep past a properly seated primer anyway.
I rotate my carry ammo every 6 months. Better safe than sorry.

Perspiration, temperature changes, exposure to chemical solvents/lubricants, whatever.....I don't want that affecting the performance of the ammunition I bet my life on.

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