NO. NEVER try to chanber ammunition in a firearm not chambered for it.
380
It ends with a 5, so it will round up to 380.
380 ends with a zero, so it is already rounded to a ten, so it is 380.
To the nearest ten, 380
380
Same round, different name
.380 ACP is a specific type of ammunition made. 380 LCP is the name of a Pistol, made by Ruger which fires the .380 ACP round.
380
A double action pistol that chambers a .380 ACP round. AKA 9mm Kurz
No, the .380 has less power than the 9mm or the .45 .
380. Last digit 5 or more middle number goes up, 4 or less you round down so stays where it is. 386 would round to 390.
380 auto. Many good brands of ammo out there.