Is 20 Rounds of 5.56 Enough?

Probably, yeah. Its enough until it isn't. Its all about probabilities, and each round of capacity increases your chance of success by less than the previous round. EG, if 10 rounds will work in 70% of cases, and 20 rounds will work in 92% of cases, and 30 rounds will work in 97% of cases - as you can tell each added 10 rounds is increasing your chances by less and less. And by the time we're going into 60 or 100 round magazines they're barely budging the success meter, because it's already darned close to 100%.

Its all about picking a number that you're comfortable with and stopping at that point. If 20 rounds works for you then carry 20.

EDIT: And just in case it wasn't clear - the percentages above are for example only and are not accurate - you'd need an actually statistical study to get the proper #'s, but they'll still generally follow the same pattern of having a diminishing return.

For my completely made up numbers:

• 99.9% of us will never need a firearm for defensive use
• Of that 0.1% that do, 99.9% will only brandish the firearm and not shoot
• Of that 0.1% that do shoot, 99.9% will end right there
• Of that 0.1% that does not end, 99.9%….

In my opinion - 20 is more than enough. Like @mgmorden says - if you are comfortable, you are good. Quantity, like caliber, is a personal decision. When I was deciding what to carry, I started with a S&W 640. Deciding 5 was not enough, I swapped to a Glock 23. Personal decision - no right or wrong

What is the threat?

-Stan

I keep a 20 rounder in the gun. A 20 allows easier shooting from prone, which, although less likely in a home defense scenario, is, I figure, as likely or likelier than needing to use the whole 20 rounder and reload.

Think about it, the US military issued 20-round mags for use in automatic weapons for decades. Even in combat you carry the rifle 99.9% of the time and maybe shoot it in anger the rest. I carried a full load of 20s in SEA and even shooting against AKs it was fine. Would 30s have been better? Maybe, but their extra weight and size would have been detrimental most of the time. Better 20s in the webgear than 30s in your hands.

That said, in a HD situation weight isn't likely to be an issue - but then you’re not using an automatic weapon are you? if you’re in a firefight defending your home you are in ‘way over your head as an individual. One man alone has little chance of “winning” a firefight against multiple tactical intruders in a home. For a single intruder - 20 should be plenty.




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That should be enough to neutralize 20 armed threats. That's a pretty bad day.

I hunt pigs with 20's. Usually only load 15. I've shot the gun dry once.

I am of the opinion that in a defensive situation, if it takes more than 5 rounds, you probably should have been running from the start.

Fantasy “Charlie” overrunning your fantasy firebase? Prolly not.

Fantasy rioters storming across your threshold? Prolly not.

Fantasy zombies out for brains? Prolly not.

Fantasy TEOTWAWKI situation? Prolly not.

Defense against small deer? More than enough

greyling22 said:

I am of the opinion that in a defensive situation, if it takes more than 5 rounds, you probably should have been running from the start.

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While potentially true, assuming that running would be an option, logic requiring determinations after the fact are largely inadequate for preplanning, LOL. You won't know if a self defense situation is going to take more or less than X number of rounds for resolution before the situation happens.

greyling22 said:

I hunt pigs with 20's. Usually only load 15. I've shot the gun dry once.

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Hunting and self defense are not logical comparisons for determination of self defense needs.

better than a sharp stick or some harse words

I preferred 20rd mags when I had an AR. I have some 20rd mag for my mini 14, but no 30s.

How many attackers do you think you'll face? How many rounds do you think you'll need per attacker? And how many times do you expect to miss?

If 20 rounds in the gun won't do it, you might need to look at your strategies, tactics and training before considering more capacity.

Just my two cents.

I keep 20s in my rifle and gear.

I keep 30s in the closet cuz they give Nancy, Chuck, and Joey the vapors.

When I wander around in the woods with my lightweight ar i usually have a 10 rounder in the gun and a 30 in my back pocket. All of my 300 blk rifles get 10 to 20 rnd Magpul mags, 20 is more than enough on board, if you have even an inkling you'll need more just have another 20 rounder handy. We aren't breaching doors in warzones with our personal defense carbines...

Like most things, the correct answer is "It depends...."

No one can answer that question but you.

Here is an interesting article on the topic: https://www.luckygunner.com/lounge/much-ammo-capacity-enough/

I prefer 20s, I buy 30s, 40s, etc because gun grabbers hate them.

All you really need is 1 or 2 shots as long as they hit the target in the right place. After the 10th shot if you still haven't done that, then 10 more should be plenty.

Twice as much as I am using.

JCooperfan1911 said:

I have a lightweight AR chambered in 5.56. I like 20 round magazines as they’re compact and keep the gun streamlined.

Is it enough firepower for defense?

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How fast and consistent are your mag changes?

Six for sure.

The guy in Indiana who stopped the mall shooter fired 10 rounds and hit the murderer with 8 from a "distance" with a handgun. How's your marksmanship?

My usual CCW gat is a 5-shot J-frame S&W .357. It sits beside my bed, so it would also be my first resort in a home-defense crisis. I have a Glock on my carry permit but it usually stays in the safe.

If asked, a 5-shooter is not the choice I would recommend to someone else. Nor am I advocating magazine limits.

FWIW, my reasoning behind the choice of a 5-shooter is that I have limited financial resources: even with self-defense insurance, I literally cannot afford to miss and absorb the liability of hitting a bystander. More to the point, I could not live with myself if I ever did. Five shots means every single one will be deliberate and as accurate as I am able to deliver, because in the back of my mind I know that's all I have available.

It might sound stupid to you but it's a good fit to my psyche. And therefore ten or twenty seems like plenty to me.

If you think you can't do it with 20, buy a shotgun.

It's plenty of ammo unless it isn't. The gunfight lasts as long ss it lasts. Your marksmanship, their marksmanship, what they are wearing, any substances they are on, how determined to finish the fight they are, their will to live, their desire to live, their mental health, how many there are, etc... ALL come into play. The other guy(s) have a say in it. In reality as they are the aggressor, they have more say in it than you do.

Most defensive shootings i have investigated have had fewer than 10 rounds fired. Most, but not all. I recently posted a story in another forum where one guy fired 15 rounds from his handgun and 30 rounds from his rifle in a home invasion scenario.

I wouldn't feel undergunned with a 20 round mag, but i only use them for shooting from a bench. I buy and use 30s.