Ammunition: the .243 Winchester caliber

A series of introductory articles conceived to teach beginners specs, features and history of the most popular rifle ammunition calibers

The .243 Winchester caliber was first launched around 1955, and was conceived simply by narrowing the neck of the then brand-new .308 Winchester ammunition to adapt its case to the use of 6mm caliber bullets.

Some history

The paternity and the origins of the design of the .243 Winchester round are disputed; some historians credit Warren Page, a well-known shooter back in the day, for the creation of this round, but most experts credit the Winchester development team, who may or may not have been heavily influenced by a 6mm caliber developed by Page himself, dubbed the .240 Page. 

Bergara Apex .243 Winchester
A hunter aims a Bergara Apex .243 Winchester caliber single-shot hunting carbine

Either way, it was a brilliant idea and its result was a powerful, accurate and versatile round with a minimum recoiul level; the 1:10" rifling pitch turned out to be perfect to stabilize .243 Winchester rounds ranging between 70 and 110 grains in weight, and this factor contributed significantly to its commercial success. 

Ammunition: the .243 Winchester caliber
A .243 Winchester caliber RWS hunting round, loaded with a 96-grains conic soft-point bullet

That marked the birth of a great round, perfectly fit to be used on short-action guns and capable to propel bullets of a higher diameter than most, if not all, of the .22s used back in the day more or less at the same velocity levels.

It was initially offered as a varmint cartridge on the U.S. market, but hunters soon found out that it was perfectly capable to bring down mid-sized ungulates such as the whitetail deer − a benchmark performance by which all big game hunting rounds are judged.

The cartridge

As we said previously, the .243 Winchester round is based on a case that is very similar to that of the .308 Winchester caliber − only slightly longer and with a shorter neck, which boosts its propellant capacity and makes it fit for 6mm bullets. 60 grains should be considered the optimal ball weight for this caliber; heavier bullets will take too much room and require a reduction of the propellant quantity contained in the case, but despite this the .243  Winchester round still provides good performance with 100-grains bullets.

Ammunition: the .243 Winchester caliber
A classic hunting load in .243 Winchester caliber: the RWS conic soft-tip 96 grains bullet
Ammunition: the .243 Winchester caliber
The Nosler Ballistic Tip 90-grain .243 Winchester load is extremely accurate and offers an extremely flat trajectory

The .243 Winchester cartridge is chambered mostly by bolt-action hunting rifles, but its intrinsic potential led gunmakers worldwide to manufacture many other rifle designs, such as Kipplauf and other single-shot platforms, chambered for it. Basically all manufacturers of ammunition offer .243 Winchester loads, with a wide array of bullet types and weights available.

Ammunition: the .243 Winchester caliber
The .243 Winchester load in the Winchester Power Point line of ammunition sports a soft-tip 100-grains ball
Ammunition: the .243 Winchester caliber
The German-based GECO brand offers a hunting-oriented .243 Winchester load with a 105-grains soft-tip bullet

The most popular loads use 80-grains and 100-grains bullets. When loaded with 80-grain billets, the .243 Winchester round can develop muzzle energy levels higher than 1000 metres-per-second (3280.8 feet per second), while 100-grains bullets can travel faster than 900 metres-per-second (2952.75 feet per second), with pressure levels ranging around the 4200 Bar threshold: a very high performance level that makes the .243 Winchester caliber excellent for a wide variety of hunting specialties.

Remington 700 SPS Buckmaster
The Remington 700 SPS Buckmaster bolt action rifle is chambered, among other calibers, for .243 Winchester
Merkel K3 DS Lady
The Merkel K3 single-shot break-open rifle is also available in a wooden stock DS Lady variant, chambered in .243 Winchester

Fields of use

In the United States, the .243 Winchester round is extremely popular for varmint, small-game and mid-size ungulates hunting.

Remington 783
The .243 Winchester caliber Remington 783 entry-level bolt action hunting rifle is offered with a factory-issued and zeroed 3-9x40mm scope

In Europe it is the post popular and commonly available alternative for roe deer hunting, and would also be more than apt for bigger and more challenging game − such as the chamois − if it wasn't for several local and national laws and regulations imposing the use of calibers larger than 6mm for most mid-sized and big game.

An extremely accurate caliber, the .243 Winchester is a pleasure to shoot, offering a very low recoil level and even lower muzzle climb − meaning that the typical reactions to the shot won't make the shooter loose eye contact with the target, enabling him/her to respond quickly to any reaction, which is paramount when hunting rare or highly sought-after game.


Warren Page, the shooter believed by many to be the father of the .243 Winchester, was also an expert in ammunition who contributed to the development of other popular hunting and sport shooting calibers such as the .222 Remington and the 7mm Remington Magnum.

The .243 Winchester is a relatively hot caliber; hand-reloaders should thus settle for a good compromise between power and accuracy rather than try and reach the highest power levels. Propellants offering a mid-to-high progressive factor should be preferred when reloading the .243 Winchester.

.243 Wichester cases could be easily obtained from .308 Winchester brass, but this practice is highly discouraged as the tightening may cause a variation of the inner shoulder angle, which would not be visible from the outside but could nonetheless cause violent and dangerous surges in pressure.

An example of reloading specs for the .243 Winchester cartridge

Gun: Ruger N.1            Barrel lenght: 54 centimeters






.243 Winchester 

IMR 4831

44 grains

80 grains Sierra SPBT

Federal 250

.243 Winchester

Vihtavuori N160

45 grains

80 grains Speer FMJ

Federal 250 

.243 Winchester

Norma MRP 

48 grains

80 grains Barnes TSX

Federal 250 

.243 Winchester
Norma MRP
46 grains100 grains Hornady SP
Remington Magnum


Our readers should be advised that ammunition handloading requires skill and attention. All provided handloading data should be considered as purely indicatory; even the slightest variations could cause dangerous pressure surges, which could in turn result into bodily harm or property damage. In no case will the author of this article or all4shooters.com accept any responsibility for any injury or damage caused by the improper use of these data.

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