Please note that this article looks at research and testing done by a variety of sources. Extreme caution should be taken when creating loads that go against accepted load data. This article looks at theory and our experience, and should not be considered recommendations about primers for the 243 Winchester. When developing a new load for your 243 Winchester, or any caliber, you should start with smaller amounts of powder and pressure and work up gradually.
About the 243 Winchester
The .243 Winchester cartridge is a rifle cartridge that was introduced by Winchester Repeating Arms Company in 1955. It is based on the .308 Winchester cartridge case and uses a .243 inch diameter bullet. The cartridge is popular for hunting medium-sized game such as deer, coyote, and pronghorn, and is known for its accuracy and low recoil. It is typically loaded with bullets weighing between 55 and 105 grains, with the most common weight being 100 grains. The cartridge is often used by varmint hunters and target shooters due to its accuracy, flat trajectory, and low recoil. In addition, the .243 Winchester cartridge is also popular for youth hunters, as its low recoil can make it easier for younger or smaller-framed shooters to handle.
The .243 Winchester cartridge is a versatile and widely used cartridge for hunting and target shooting. Selecting the right primer size for this cartridge is critical to ensure consistent ignition, optimal performance, and accurate shooting. In this blog post, we will explore the different primer sizes available for the .243 Winchester and their effects on pressure, velocity, and accuracy. Understanding primer size is an important aspect of handloading this cartridge and can help you achieve your desired performance. Whether you’re looking to maximize accuracy, achieve a specific velocity, or simply maintain reliable ignition, this post will guide you in choosing the right primer size for your .243 Winchester loads.
What Size Primer for 243
The 243 Winchester cartridge uses a large rifle primer. This is standard primer size used for centerfire rifle cartridges .30 caliber and larger. Most all reloading manuals list the large rifle primer. I always like to check 2 or 3 manuals when doing load development for a new load. Some people do experiment though with other primers.
Lyman Reloading Manual
Using Large Rifle Magnum Primers for 243 Winchester
Especially when there’s a primer shortage, people often wonder if they can use other primers in their reloading. More than any other question about 243 Winchester reloading, I get asked if you can use large rifle magnum primers for 243 Winchester.
I’m going to reemphasize, standard large rifle primers are recommended for the 243 Winchester cartridge, as they are designed to ignite the powder charge in cartridges with case capacities and pressure similar to the 243 Winchester. It’s important to always use the correct primer size and type for the cartridge you are loading to ensure safe and reliable performance. It is recommended that you always follow the manufacturer’s recommendations and industry standards when reloading any cartridge. That said, many people have experimented with magnum primers, and some have even found some success.
Hornady Handbook of Cartridge Reloading
Magnum primers are designed to ignite the powder charge in cartridges with larger case capacities and higher pressure than standard cartridges. They have a hotter and longer lasting flame which helps to ignite the slower burning powders used in magnum cartridges. However, the 243 Winchester cartridge is not considered a magnum cartridge and it uses standard powders, and using magnum primers can result in higher pressure and potentially dangerous situations. If you want to experiment with magnum primers, start with a smaller load, and work up safely and carefully, watching for signs of danger and pressure. You are literally playing with fire, so be EXTRA careful.
Can I Use Large Pistol Primers in the 243 Winchester?
No. You cannot and should not even try to use large pistol primers in the 243 Winchester. Large rifle and large pistol primers are not the same dimensions. A large pistol primer is a little smaller. A small pistol and small rifle primer are the same dimensions, and there is a little bit more capacity for experimentation (and some people do with 40 S&W primers and 300 Blackout primers). Not so with large rifle and large pistol primers. Your firing pin won’t be spaced to strike consistently, to say nothing of the pressure problems. The 243 Winchester uses a lot of pressure and powder. Don’t try it. The same goes for large pistol magnum primers. It’s not remotely safe or compatible. Don’t do it.
Possible Primers to Use in 243 Winchester
- CCI 200 Large Rifle
- CCI BR2 Match
- Federal 210 Large Rifle
- Federal 210M Match Large Rifle
- Winchester WLR
- Fiocchi Large Rifle Primer
- Norma Superflash LR
- Remington 9 1/2 LR
- Sellier and Bellot Large Rifle
Possible Magnum Primers to Experiment With for 243 Winchester
- Federal 215M Magnum Match
- Federal 215
- Remington 9 1/2 Magnum
- CCI 250 Magnum
About Primers
The primer is the small, cylindrical component that sits in the base of the cartridge and contains a small amount of an impact-sensitive explosive mixture. When the rifle’s firing pin strikes the primer, it ignites the mixture, which in turn ignites the powder in the cartridge and propels the bullet out of the barrel. The primer is an essential component of the cartridge and is responsible for initiating the firing sequence.
We recommend the CCI 200 Large Rifle or the CCI BR2 Match primers. Some also experiment with the magnum primers, but we prefer the CCI 200 or BR2 for the 243.
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