There are several .380 handguns made by several manufacturers, and thus there are several designs and consequentially, several different takedown procedures. You would need to specify what make and model of .380 handgun you have in order for this question to be answered.
The .380 automatic cannot shoot 9mm Parabellum ammo.
have a gunsmith do it to avoid damage to gun
Gun show, want ads, gun shop
380 auto. Many good brands of ammo out there.
Try want ads, gun shows, gun shops.
Russian made
Blue Book of Gun Values
2mm in case length.
100-1000 depending on exactly what you want/have.
The different between the two is the prime and grain. Just like a 50 cal rifle and the 50 cal hand gun. If the prime was the same it would be pretty nasty for the person shooting the hand gun
You don't define what "better" means to you. Price? Size?
what is the value of a 1919 colt automatic hand gun