.38 S&W

.38 Smith & Wesson
A box of WWII-dated .380" Revolver Mk IIz cartridges (and separate cartridges)
Type	Revolver
Place of origin	United States
Production history
Designer	Smith & Wesson
Designed	1877
Manufacturer	Smith & Wesson
Variants	.38/200
Specifications
Bullet diameter	.361 in (9.2 mm)
Neck diameter	.3855 in (9.79 mm)
Base diameter	.3865 in (9.82 mm)
Rim diameter	.440 in (11.2 mm)
Rim thickness	.055 in (1.4 mm)
Case length	.775 in (19.7 mm)
Overall length	1.240 in (31.5 mm)
Ballistic performance
Bullet mass/type Velocity Energy 158 gr (10 g) L SWC 767 ft/s (234 m/s) 206 ft·lbf (279 J) 195 gr (13 g) L RN 653 ft/s (199 m/s) 185 ft·lbf (251 J) 200 gr (13 g) LRN 620 ft/s (190 m/s) 176 ft·lbf (239 J)

The .38 S&W (9×20mmR) is a revolver cartridge developed by Smith & Wesson in 1877 for use in the S&W .38 Single Action. Though similar in name, it is not interchangeable with the later .38 Smith & Wesson Special due to a different case shape and slightly larger bullet diameter.

The British military adopted a loading of this cartridge as the Cartridge, S.A., Revolver Ball, 380 in, MkI .38-200, with the "200" referring to the weight of the bullet in grains. In 1937, this cartridge was replaced in British Service by the Cartridge, S.A., Revolver Ball, 380 in, MkII. The main difference between it and the previous round was that it had a 178 gr (11.5 g) FMJ bullet.

The .38 Colt New Police was Colt's Manufacturing Company's proprietary name for what was essentially the .38 S&W with a flat-nosed bullet.

The U.S. .38 S&W Super Police cartridge was nearly identical to the British .38/200 Mk I, using a 200 gr (13 g) lead alloy bullet with a muzzle velocity of 630 ft/s (190 m/s) and a muzzle energy of 176 ft·lbf (239 J), and was supplied by several U.S. manufacturers to the British government as equivalent to the Mk I loading.

MKE's 9.65 mm Normal [9.2x23mmR (.38 Smith & Wesson)] cartridge has an 177 gr (11.5 g) lead-antimony alloy bullet with a gilding-metal full metal jacket and a Boxer-primed brass case. The "Normal" designation differentiates it from their 9.65mm Special [9.1x29mmR (.38 Special)] round; it uses the 9.65 mm (.38-caliber) nominal bore rather than its 9.2 mm (.361-caliber) actual bore. It has a muzzle velocity of 590 ft/s (180 m/s) and a muzzle energy of 21,335 lbs/inch² [1500 kg / cm²].

Currently only Ruger makes limited runs of revolvers in this caliber for overseas sales, and only a few companies still manufacture ammunition. The majority that do offer it in only a 145 gr (9.4 g) lead round nose bullet, though Fiocchi still markets FMJ rounds. Some companies such as Buffalo Bore manufacture self-defense or hunting variants.