21 SHARP – New Rimfire Cartridge from Winchester

Hrachya H
by Hrachya H
21 Sharp SAAMI cartridge drawing

SAAMI (Sporting Arms and Ammunition Manufacturers’ Institute) have published cartridge and chamber drawings of a new rimfire cartridge called 21 Sharp which was developed and submitted for SAAMI acceptance by Olin Winchester. While this new cartridge uses a non-heeled projectile, it has a lot of similarities with the 22 Long Rifle. Let’s take a closer look at the design of the new 21 Sharp rimfire cartridge.

New SAAMI Approved Cartridges @ TFB:

The new 21 Sharp cartridge not only operates at the same Maximum Average Pressure of 24,000 psi and has the same overall length (1″) as the 22 LR, but it also apparently uses the 22 Long Rifle cartridge case – case dimensions of the two cartridges are literally identical. So looks like Winchester engineers created this cartridge by simply designing a non-heeled bullet that fits the 22 LR case which resulted in a non-standard bullet diameter of .2105″ (5.347mm).

21 Sharp SAAMI chamber drawing. To download the full SAAMI cartridge and chamber drawings document, click HERE.

Per SAAMI specs, the 21 Sharp launches a 25-grain projectile at a muzzle velocity of 1,725 feet per second. The length of the SAAMI test barrel is 24″ and the twist rate is 1:12″. The bullet shape shown in the SAAMI drawing is for illustrative purposes only. With the overall length, rim dimensions and MAP being identical to 22 LR, it should be easy to convert 22 LR firearms to 21 Sharp by simply swapping the barrels. The actual release of the new cartridge and firearms chambered in it will hopefully follow the SAAMI standardization. It’d be interesting to see what types of bullets 21 Sharp will be loaded with and which markets it is primarily designed for.

Pictures by SAAMI, www.saami.org

Hrachya H
Hrachya H

Managing Editor Being a lifelong firearms enthusiast, Hrachya always enjoys studying the history and design of guns and ammunition. Should you need to contact him, feel free to shoot him a message at Hrachya@TheFirearmBlog.com

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  • DD DD on Jul 18, 2023

    The only way this would make sense would be if a gun chambered in .21 Sharp could also fire cheap .22 LR. Now, I'm not going to be the first one to try that, but I'm sure that within a week of its introduction, plenty of people will try it. Same exact case, same exact pressure, only 0.01 difference in bore diameter, so it seems to me that .22 LR should safely fire in a .21 Sharp firearm, with only a slight loss in accuracy (like firing 9mm in one of those Ruger convertible revolvers that can fire both .357 Magnum (.357 bore) and 9mm (.355 bore). Disclaimer: if the manufacturer says not to do it, don't do it, but if the manufacturer says it's safe, as I predict they might, then you can go ahead.

  • Don Pleu Don Pleu on Aug 08, 2023