9×23mm Winchester

9×23mm Winchester
9×23mm Winchester (left) compared with 9×21mm (center) and 9×19mm Parabellum (right)
Type	Pistol
Place of origin	United States
Production history
Designer	Winchester Ammunition (John Ricco) (Anthony Valdez)
Designed	1996 (1994)
Specifications
Parent case	.38 super
Case type	Rimless, straight
Bullet diameter	9.04 mm (0.356 in)
Neck diameter	9.68 mm (0.381 in)
Base diameter	9.93 mm (0.391 in)
Rim diameter	10.01 mm (0.394 in)
Case length	22.86 mm (0.900 in)
Overall length	33.02 mm (1.300 in)
Primer type	small pistol *Some people use small rifle primers
Maximum pressure	55,000 psi
Ballistic performance
Bullet mass/type Velocity Energy 124 gr (8 g) Win USA JSP (.180Bc) 1,460 ft/s (450 m/s) 587 ft·lbf (796 J) 124 gr (8 g) Win JSP @ 50yds 1,308 ft/s (399 m/s) 471 ft·lbf (639 J) 125 gr (8 g) Super-X Silvertip HP (.129 Bc / 5" Bbl) 1,450 ft/s (440 m/s) 583 ft·lbf (790 J) 125 gr (8 g) Super-X @ 50 yds 1,249 ft/s (381 m/s) 433 ft·lbf (587 J) 125 gr (8 g) Super-X @ 100yds 1,103 ft/s (336 m/s) 338 ft·lbf (458 J)
Test barrel length: Varied Source(s): Winchester Ammunition; C.I.P.SAAMI

The 9×23mm Winchester is a pistol cartridge developed as a joint venture by Winchester Ammunition and Colt's Manufacturing Company. The 9×23mm Winchester has a convoluted development history, but was commercially introduced by Winchester in 1996. Marketed primarily to competition shooters as a replacement for .38 Super for International Practical Shooting Confederation, United States Practical Shooting Association and International Defensive Pistol Association competition, the cartridge made a splash, but never really caught on.

The critical design feature of the 9×23mm Winchester is a much-strengthened case that does away with the semi-rimmed case design of the .38 Super which sometimes caused feeding problems. The strengthened case allows the 9×23mm Winchester to operate under a higher internal pressure, 55,000 psi (measured with a piezoelectric transducer), in comparison to the maximum pressure of 36,500 psi for the .38 Super (current SAAMI standards). It has a slightly tapered but nearly parallel case which means that it has greater magazine capacity for the same 9 mm bore diameter relative to the necked down cases of the .357 SIG, 9×25mm Super Auto G, or 9×25mm Dillon. To achieve enough propellant capacity for the power needed the 9×23mm Winchester is longer than the 9×19mm Parabellum or .357 SIG and so requires the extra magazine front to back length of a 1911 style magazine.

Patent 5,187,324 was filed by John Ricco of CP Bullets in 1992 for an "improved 9mm cartridge casing" that he called the 9×23mm Super. He had the prototype brass casings made by Winchester Ammunition. They then modified the design slightly and filed it under patent 5,507,232 in 1995. In comparison to the popular 9×19mm Parabellum, Winchester had lengthened the overall case by 4 mm and made it much stronger. They named it the 9×23mm Winchester. In comparison to the long established .38 Super Auto, also a 9×23mm, the new cartridge was rimless rather than semi rimmed.