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The 9x23mm was specifically designed for the needs of sport shooters who wanted a 9mm caliber cartridge that would meet the USPSA major power factor standard. Unfortunately, the cartridge was caught in legal issues early in its life and struggles to find a place in the competition world. Learn More

History of 9x23mm Winchester Ammo

The development and manufacturing history of 9x23 Winchester ammo is somewhat complicated due to its original intention, modifications, and legal issues. It was developed through a collaboration between Winchester Ammunition and Colt Manufacturing Company in the 1990s, and was introduced to competition shooters as a replacement for the .38 Super. Shooters affiliated with the The United States Practical Shooting Association (USPSA), the International Defensive Pistol Association (IDPA), and the International Practical Shooting Confederation (IPSC) had been experiencing catastrophic failures because they were trying to reach major power factor by combining firearms and calibers that were ill suited to such high pressures. To solve the ongoing problems, the 9x23mm Winchester was designed to permit safer and faster shooting by sport shooters, while still providing major power factor.

Major Power Factor and the 9x23mm

To be considered a major power factor for competition in these disciplines, the ammo must meet certain criteria. If the requirements are met, the shooter will not incur scoring penalties for minor power factor ammunition.

Power factor is calculated by multiplying the bullet weight times the velocity and dividing the result by 1,000. In 1996, the minimum score to be considered major power factor was 175. A .38 Super would need a bullet weighing 130 grains and would need to travel at 1,350 feet per second to qualify as major. This was possible for a .38 Super, but it was also close to safety limits.

In the end, there were enough problems to motivate Winchester Ammunition to collaborate with Colt Manufacturing Company for a solution. They developed a cartridge that combined the increased magazine capacity of bullets with a diameter of 9mm. The result was the 9x23mm Win, capable of handling the higher pressures generated by pushing a bullet that size to major power factor velocities.

The 9x23mm Winchester bullet diameter was the same as the .38 Super, so competitors already had many of the necessary components for loading their own ammo. The similarities, however, between the .38 Super and the 9x23mm end here. John Ricco designed the strengthened case in 1992, which allowed about 25 percent higher case pressures for the 9x23 – calling it the 9x23 Super.

A critical feature of the 9x23mm Winchester, aside from the strengthened case, is that it eliminated the semi-rimmed case of the .38 Super, the culprit behind that round’s continued feeding problems. The strengthened case also permitted the round to function using a higher internal pressure, 55,000 psi compared to the maximum pressure of the .38 Super, which is 36,500 psi (current SAAMI standards).

The IPSC reduced the major power factor during this time from 175 to 165, which made the .38 Super a safe choice for shooters. This struck a blow to the popularity of the 9x23, since there were many users of the .38 Super. As a result, the 9x23mm became a novelty cartridge.

Unfortunately, perhaps due to its origins, it has never been accepted as a cartridge for personal protection – even though the ballistics of the 9x23mm are better than the .357 SIG, including a higher magazine capacity.

Ricco vs Winchester

While the 9x23mm did not get produced until the 90s, the original concept of the round was invented in the 1930s. Decades later, it was retooled and introduced as the 9 Super Cooper. Fast forward a few more years to John Ricco of CP Bullets (now Classic Pistol), and Ricco pondered over how to make the cartridge better. He examined the specs, made some modifications to the design, and renamed it 9x23mm Super.

When the cartridge was finally ready to be produced, Ricco approached Winchester to create a prototype brass casing that would improve the round. In 1992, Ricco filed a design patent on the 9x23 Super, claiming an "improved 9mm cartridge casing." Winchester modified Ricco’s design by lengthening the case by 4mm and changing the angle of the extractor groove. By 1995, they filed a patent for their 9x23mm Winchester. The round was thought to be superior because unlike the .38 Super Auto, the new cartridge was rimless.

Touted as "The strongest case ever built for a centerfire cartridge," Winchester introduced its new design at an NRA convention in 1996. The company claimed that the cartridge had the lowest recoil while still qualifying for the major power factor designation with the IPSC. The power factor (PF) is calculated by taking the bullet weight in grains, multiplied by the muzzle velocity, and divided by 1,000. The IPSC required a minimum of 175 to qualify in their competitions. Qualifying for the MPF was crucial as a Minor Power Factor incurred scoring penalties.

The most important benefits of the 9x23mm Winchester included the fact that more rounds fit into the magazines, thereby reducing the number of necessary magazine changes. The higher operating pressure of the 9x23mm Winchester meant that shooters were able to return to their targets in less time than those using a .45 pistol of identical design. Since IPSC competitions consider speed in their scoring system, competitors using this round had a better chance of receiving higher scores.

This double benefit of using the 9x23mm Winchester during competition prompted Ricco to seek legal action against Winchester. While the case was pending, Winchester’s hands were tied, and production was halted. Seven years after filing, Ricco won his case. And since the IPSC had changed its regulations regarding the power factor limit as well as the 9x23mm Win no longer in production, competitors were forced to find other options.

Shooters had been using pistols based on the 9mm and .38 Super Auto, but they had been exceeding safety limits, causing guns to blow up. By the time Winchester increased its pressure ceiling and returned to market, the demand was gone and the round was all but obsolete. The downfall of the 9x23 Win could have been avoided if Winchester had the foresight to make the bullet desirable to the mass market rather than focusing solely on competition shooters, a rather narrow demographic. Colt and other major manufacturers ceased production on pistols chambered for the 9x23 Win, sealing its fate.


Considering the longevity of some rounds on the market, the 9x23mm Winchester is relatively young at just over 20 years old.

When the round was introduced, one writer compared the hype to promises made during a political campaign. Walt Rauch, firearms enthusiast, author and founding member of the International Defensive Pistol Association, had this to say about the 9x23 Win:

"The 9x23 has the ability to be to the future what the .38 Super was to the 1920s. Both have a flat trajectory, high velocity and, now, adequate bullet design – the. 38 Super lacks the higher velocity of the 9x23mm but they both share the same Winchester Silvertip 9mm bullets. Both lack a wide choice of bullet configurations. If the ammo companies get interested in this updated version of a long 9mm, the potential is there for an excellent small game and personal defense round. Both rounds are only hindered by the need for a large frame semi auto to handle them."

Rauch’s words were prophetic. The case length of the 9x23 requires a 1911 platform, which was a hindrance unless you are into conversions, modifications or taking unnecessary risks. Since it was easier for manufacturers to produce pistols for a standard 9mm, the 9x23 was doomed to fail, much to the chagrin of its supporters.


Although the 9x23 has been largely off the market since the 1990s, enthusiasts continue to compare it to other rounds, especially the .38 Super, 9mm, .357 SIG and .45 ACP. The 9x23mm was originally designed to be used in a Colt pistol, like the 1911, and there are few if any guns on the market specifically made to handle the round the way it was intended.

It performs similarly to, and perhaps even exceeds the performance of, the .357 SIG because of its higher pressures. The higher magazine capacity should have more impact on the comparison, although the 1911 wasn’t as desirable for personal defense as the .357 SIG 9mm, and .40 S&W. The .45 ACP, also originally designed for competition shooting, has a similar length, but does not require the same large automatic frame as the 9x23. The same can be said for the 10mm.

Substituting other rounds for the 9x23mm Win or using other weapons that may be able to fire the round are common questions in gun forums. Some claim that the round can be fired in .38s – but that’s a dangerous game to play, as the 9x23 fires much hotter and the space in the .38 barrel is not appropriate. The same can be said for using it in a 9mm Luger or similar model.


When it comes to reloading cartridges for the 9x23 Winchester, one must consider the types of cases to use. The two main contenders seem to be the original Winchester case or Starline’s 9x23mm Comp. It’s important to understand that the internal capacity of these two cases are slightly different so that the maximum load will be different for each. Also, Starline’s cases have thinner walls than Winchester’s original cases, and therefore cannot withstand the same amount of pressure in a chamber that is unsupported.

Because of the sturdiness of its construction, the case for the 9x23mm Winchester is long-lasting and ideal for reloading. The sides have a slight taper, which means that there is a great reduction in friction loads after a few millimeters of extraction. One of the big issues with reloading this round is the type of primer used. Experts swear by smaller, rifle-sized primers, as they are able to withstand the high pressure.

In an article at the Free Library, Ron Reiber of Hodgdon shared this information:

"The 9x23 is not a cartridge where we have reloading data. The Winchester powder that would be ideal for this cartridge is the new (2 years ago) AutoComp. Memory tells me that Winchester loaded factory ammo with a powder made by St. Marks Powder Company, called WC 291, but I cannot readily confirm that. Nonetheless, AutoComp is of that bum speed but newer and better technology, and ideal for the cartridge. That said, I do not have any data for it, nor do I have a pressure barrel in that cartridge.
"Now, with all that discussed, the 9x23 is the same case as the 38 Super, just changing pressures from a max of 33,000 CUP for the 38 Super to a max of 46,000 psi for the 9x23. Knowing capacities are very close to the same, albeit a bit less capacity on the 9x23 due to a bit thicker dimension in the head area, you can start with 38 Super data, and once you reach maximums, go up a couple tenths at a time, where an increase of a half to .6 grain will probably get you max for the 9x23."

While the procedure for reloading the cartridge is not difficult, getting accurate information on the specs is not as easy. Most information varies from that found on Wikipedia and Winchester, two of the more reputable sources. Ironically, Winchester no longer carries the round or the original extra heavy brass cases. Winchester's Reloading Component Catalog offers limited, but helpful, information.

Despite the near-obsolescence of the cartridge, there are still diehard fans that won’t let it go. Many of those supporters claim that it would be the ultimate submachine gun round as well as being a top-notch choice for use in military sidearms. They claim that the round would hit harder, have less recoil, give better armor penetration, be easier to suppress, and emit less noise. To date, there has been no success in convincing firearms manufacturers to revive production on appropriate weapons for the 9x23mm Winchester.

9x23mm Winchester Ballistics: Chart of Average 9x23mm Winchester Ballistics

Note: This information comes from the manufacturer and is for informational purposes only. The actual ballistics obtained with your firearm can vary considerably from the advertised ballistics. Also, ballistics can vary from lot to lot with the same brand and type load.

9x23mm Winchester Bullet WEIGHT Muzzle VELOCITY (fps) Muzzle ENERGY (ft. lbs.) Mid-Range TRAJECTORY (in.) Barrel Length (in.)
  Muzzle 50 yds. 100 yds. Muzzle 50 yds. 100 yds. 50 yds. 100 yds.  
124 Grain 1190 1055 966 390 306 257 0.7 3.7 4"
125 Grain 1450 1249 1103 583 433 338 0.6 2.8 n/a
Molly Carter
Written by
Molly Carter