I'm looking at carry guns and would greatly appreciate some help with understanding the rounds involved. I see guns that say 38 special or 38 special +P or 380 or .357 mag but I don't understand these rounds. It seems to me that the 357's also shoot the 38 specials (kind of like a 44 mag and a 44 spl) but how can that be when .38 does not equal .357??? I'm pretty sure I understand the 380 acp but would it shoot in a 38 special gun? .38 specials look a lot like a .357mag but are they similar in power or is the 357 a much more stout round? Is a "38" the same as a 38 special?
I'm leaning on buying a small .357 with the expectation that I can run lighter loads in it (38 special?) to practice most of the time. Unfortunately, I don't understand enough about this size round to know what I don't know and what else I might want to consider.
Any help and comments would be appreciated.
380ACP and 9mm bullets are .355" diameter. The 9mm is 9x19mm (diameter, & length), a 380ACP is 9x17mm, aka 9mm Corto, or 9mm Kurtz which both mean 9mm Short. Both are rimless cartridges and head space on the forward edge or "lip" of the cartridge. Because of this you cannot fire a 380ACP cartridge in a 9mm chambered semi automatic pistol. (You can fire a 380ACP in a 9mm revolver however as the cartridges are placed in moon clips that create a rim on which to head space.) 380ACP ammunition bullets are 90-102grs, while 9mm ammunition bullets are typically 115, 124, and 147 grains. Because the 9mm case is 2mm longer than a 380 case; it can hold more gunpowder, and, also accommodate longer, heavier bullets.
38 Special and 357 Magnum cartridges are .357" in diameter. A 38 Special case is approximately 1.145" long, and a 357 Magnum measures about 1.280". Both cartridges are rimmed and thus head space on the rim, same as a 30/30 Winchester®, 22lr, or shotgun ammunition. Because of this any 38 Special cartridge can be fired in a 357 Magnum revolver. You cannot however fire a 357 Magnum cartridge in a 38 Special revolver. The cartridge is too long and thus will not chamber correctly. 38 Special ammunition is typically available in 110, 125, 130, 135, 148, and 158gr bullets. 357 Magnum ammunition is loaded with 110, 125, 135, 140, 145, 158, and 180gr bullets. 38, and 38 Special is a ubiquitous term. Originally upon its introduction in 1899 (black powder), & 1902 (smokeless powder); the cartridge was called the 38 Smith & Wesson® Special. Now days if anyone says 38 or 38 Special it means this cartridge.
Of the four calibers you cite; the 357 Magnum is the most versatile and the most powerful. What will you use the gun for, home defense, concealed carry, or both? If strictly for home defense and range use, a 4-6" barrel will be superb. If for concealed carry however, you will be better served with a snub nose 1⅞-2½" barrel revolver. With the shorter barrel length the gun will be easier to conceal, and also faster to draw.