Depends on the pistols. A full frame revolver will be larger than a subcompact automatic, and vice versa. As for the cartridges, it depends on which .38 you had in mind... .38 Special usually comes to mind, but there are a number of cartridges branded as .38 (.38 S&W Long, .38 Super, etc).
A 9mm pistol is a pistol that fires a bullet which is 9 MMs in diameter.
The 9 mm is preferred over the 38. The two bullets are about the same size and frequently will work from the same pistol. Police departments that used to use the 38 have gone over to the 9 mm or 45. If you are shooting in international competitions, you would need 9 mm. 38 would be useless. Any strictly American sizes will become useless. Before long, it will be almost impossible to get ammunition for a number of 32 caliber pistols. So, if you are getting a pistol, get one that will have use down the road.
Millimeters, it is the size of the bullet.
No
If you mean the 9 mm Parabellum AKA 9x19 mm or 9 mm "Luger", the .38 Special is physically larger. The case length of the .38 is 0.401 inches longer. The over all loaded cartidge length of the .38 is 0.381 inches longer. Case diameter is nearly identical between the two, but the .38 has a larger rim/case head by 0.046 inches. The 9 mm fires a 0.355 inch diameter bullet whereas the .38 fires a 0.357 inch diameter bullet.
100-400 USD
Yes. .38 special is a revolver cartridge and .380 is an auto cartridge. Also, the .38 will almost always have a heavier bullet and more muzzle energy than a .380. The .38 bullet is 0.357 inches in diameter while the .380 is 0.355 inches in diameter. Technically, the .380 cartridge is considered part of the 9 mm class of bullets. [9 mm x 19 mm = 9 mm Luger or 9 mm Parabellum, 9 mm x 18 mm = 9 mm Tokarov, and 9 mm x 17 mm = .380 ACP]
A 50 calibre machine gun can have any length or width. The inside of the barrel is 1/2 inch. Gradually calibre as a gun size is being dropped in favor of metric. For example 9 mm is replacing 38 calibre. A 38 calibre pistol will shoot a 9 mm bullet. Mortars are now 61 mm instead of a calibre.
50-250
Yes they is a differnent. When people say "38" they usually mean .38 special, which is a revolver cartridge. .380 ACP is a semi-automatic cartridge. The bullet in a .380 cartridge, even though it's called .380, is actually very slightly smaller in diameter, and lighter than the bullet in a .38 cartridge. The .38 bullet is 0.357 inches in diameter while the .380 is 0.350 inches in diameter. Technically, the .380 cartridge is considered part of the 9 mm class of bullets. [9 mm x 19 mm = 9 mm Luger or 9 mm Parabellum, 9 mm x 18 mm = 9 mm Tokarov, and 9 mm x 17 mm = .380 ACP]
If they carry a gun at all, it is usually the M9 pistol, or a colt or S&W .38 Special revolver. ---- The .38 is rarely seen in the military any more. The primary handguns are the M9 Beretta 9 mm or the M11 SIG Sauer 9 mm (SIG P228).
A Jennings model 59 9 mm is a type of pistol. Many people try to sell this pistol for anywhere between seventy dollars and over two hundred dollars, the value is determined up the use and care of the pistol.