There’s an age-old debate about the best ammo size. Here, lets specifically talk about .380 and 9 mm.
Joel T. Nadler does a great comparison of the two in his blog post:
https://www.usconcealedcarry.com/blog/380-vs-9mm-a-comparison-of-eight-handguns/
I’ve got one of each (.380 and 9 mm) - I won’t say what exact firearms I have, but you can probably guess if you’ve seen my other posts throughout the Community.
0 voters
@Dawn. The best ammunition size is the size that you like, can easily afford, and are good at hitting your targets at various distances.
On my EDCs the company has made 9mm conversion sets so I can practice with my gear ‘cheaper.’ Funny thing is, back when 9 was the “new” military round - it was enough; now it’s moreso. (And 380 got expensive.) So now I’ve got three SIGs with 9 and am still net 3 9mm guns… I sold the Uzi.
While the .380 is a good round, I prefer the 9mm. Mainly due to the price point. If I was pocket carrying or on ankle, I might consider a .380 for that. Just not a fan of either carry position.
Yes Sir James right you are
I chose 9mm primarily because I have no experience with anything else. However, it is my firm belief that a .380 will kill you just as dead😳, so, I do not see how you can go wrong with either caliber, IMHO…
9 mm of course…
why? there is a reason:
ok, ok… just kidding 
as price-per-round, the 9mm is unbeatable
Of these 2, 9 mm would be my choice. Ammo selection, availability, and price point. Add in the physics of velocity vs expansion, and the 9 would be a better choice for me. If I wanted to carry such a small round😏(sorry, I couldn’t resist😂)
9mm or bigger for me. I have owned .380’s, and might in the future, but I think 9mm is better.
Note: I am not volunteering to be shot with a BB gun either. 
My wife shoots a 380 so I have one as my back up. It has come a long way but it just doesn’t have the penetration of the 9mm. I think it’s place is inside 5yds.
The 9mm has the penetration I’m ok with and the availability to properly train with a firearm.
But that is me, 2 9’s and a .380 for my wife. I also like the 9x18 and the 7.62x25, both have their place.
I have debated this issue and always land on 9mm for two main reasons. First, 9mm is available pretty much anywhere in the world. Second, it is very cost effective.
Just what caliber does a Bad Guy prefer to be shot with? The answer is neither.
In my simple mind it comes down to, which round can I consistently deliver on target? For me, it’s the round I can practice with. Because the cost of .380 is double that of 9mm, I have settled on the 9. 2,600+ rounds over the past couple years, in two different pistols.
Don’t get your underwear wrapped around the axle arguing about the ballistics. Carry the gun you’re comfortable and proficient with.
Great point, @Paul1!!
so… Ask first, then shoot? 
9 is good enough for the FBI it is good enough for me.
the wife likes her 380s and that is better than not having anything
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I carry a 9mm away from home, and a .380 at home. The .380 works best in my house coat pocket.
I always felt 9mm was the minimum until I fired my friends .380 which I was surprised at first on the recoil. Same goes for the old school surplus Makarovs I suppose.
I switched to 9mm this year with my Glock 26, I bought my 9mm upper and using EndoMags with my standard AR15 lower and I just finished my Glock 22 conversion to 9mm.
I have the following calibers and plan on keeping it reserved to this
.22lr
9mm
.40SW
.45ACP
.223 rem
5.56mm
.300 Blackout
12Ga
.308
9mm also known as 9x19 and the .380 is 9x17. A 9 will not cycle through a .380 firearm. A .380 may cycle through a 9 mm firearm but it’s not a good idea.
As a policy matter, I know several local PDs that have policy of nothing smaller than .380 for off duty or backup carry.
