“If you need more than X rounds, you shouldn’t be there in the first place!”
“If you can’t solve the problem with X rounds, you shouldn’t be carrying a gun!”
“What do you need all that ammunition for?”
If you have ever discussed the idea of carrying a spare magazine in some circles, you have likely heard one or all of the above statements. People often struggle with the idea that you might have to empty an entire magazine and then load new one before continuing to shoot in a defensive situation. If the commonly stated statistics about how many times people shoot in the “average” gunfight are to be believed, they may be right to be a little incredulous… or at least they would be if increasing your firepower was the only, or even the most important, reason to carry a spare magazine.
What causes the majority of malfunctions in a good quality firearm? In my experience, that would be magazines that decide to go rogue and bad ammo is in a not too distant second place. You often can’t tell which mags and ammo are the bad ones from looking so the best way to fix a magazine or ammo problem is to get rid of the offending magazine/ammo and replace with new magazine/ammo.
Think about how you fix a double feed. After you rip out the current magazine which is likely bound in the gun under significant tension because of the rat’s nest in the chamber, would you rather reinsert it or grab a fresh magazine from your belt? I know what I would rather do.
The above statements miss the point, or at least part of it. Increased capacity is only one of the reasons to carry a spare magazine. The other reason is to correct a malfunctioning firearm. Think about it.