9mm Mars

9 mm Mars
Type	Pistol
Place of origin	United Kingdom
Production history
Designed	1899
Manufacturer	Kynoch
Specifications
Case type	Rimless, bottleneck
Bullet diameter	9.14 mm (0.360 in)
Neck diameter	9.79 mm (0.385 in)
Shoulder diameter	11.92 mm (0.469 in)
Base diameter	12.14 mm (0.478 in)
Rim diameter	11.81 mm (0.465 in)
Rim thickness	1.07 mm (0.042 in)
Case length	26.32 mm (1.036 in)
Overall length	36.23 mm (1.426 in)
Ballistic performance
Bullet mass/type Velocity Energy 156 gr (10 g) FMJ 1,400 ft/s (430 m/s) 675 ft·lbf (915 J)
Source(s): Textbook of Automatic Pistols MUNICION.ORG

The 9 mm Mars is an experimental centerfire pistol cartridge developed in the late 19th century based on necking down the .45 Mars Long case. The bullet has two deep cannelures, and the case is crimped into both. The case mouth is chamfered on the outside to fit flush into the forward cannelure. This elaborate bullet seating was necessary to withstand the violent feed mechanism of the Mars Automatic Pistol. The cartridge headspaces on the shoulder adjacent to the neck. The case has a thin rim and deep extractor groove in comparison to most rimless pistol cartridges. There was a very similar 8.5mm Mars cartridge firing a 139 grain bullet at 1550 feet per second. The Mars cartridges were publicized as the most powerful handgun cartridges through the early 20th century; but less than 100 pistols were made and manufacture ceased in 1907.

...
Wikipedia