If you’ve ever fired a gun, it’s likely you’ve wondered about the processes that cause such a powerful force to be created. With a slight motion of the pointer finger, a projectile is launched through a burst of fire faster than the eye can see. The projectile strikes its target with force large enough to penetrate most materials. What is it that allows for such a massive force?
The operation of a rifle is intuitive, but there are many underlying processes set into action that can be less clear, all of which occur in a fraction of a second. When you pull the trigger, you start that series of mechanisms and reactions that cause the round to fire. The entire process is reliant on the spark that sets it all off. This spark originates from the primer.
If you’re new to rifle shooting, you may not be familiar with the nuances of choosing the right primer for your firearm. This can result in reloading jams or accuracy problems, a frustrating issue when you’ve spent good money on your ammunition. This is why it’s crucial to understand the differences between rifle primers, and which is best for your rifle of choice.
Learning how to do so is easier than you may think. This guide will walk you through the basics. We’ll look at what exactly a primer does, the differences in size, and how to choose the best one for your needs. Let’s jump right in.
What are Rifle Primers?
The primer is the bottom part of a bullet that is struck by the firing pin when a trigger is pulled. It is a small capsule that contains an explosive mixture. When the pin hits it with sufficient force, a chemical reaction is initiated which produces extreme heat and pressure, propelling the rest of the projectile out from the cartridge and through the rifle’s barrel.
The history of the rifle primer goes back hundreds of years, with the invention of the flintlock. The earliest iterations of the technology used flint to ignite a powder charge made from mercury and potassium chlorate. This mixture was separate from the round itself, poured directly into an opening behind the main charge.
This technology was greatly prone to misfire under wet conditions or with poorly maintained parts, as the black powder quickly created residue inside the barrel with each shot. The large shower of sparks produced when fired could even ignite another person’s powder charge. This is one of the main reasons that soldiers using flintlocks would volley between salvos.
Misfires and inefficient reloading were major drawbacks to their use, and eventually, the technology progressed to the much more reliable primers we have today.
Understanding What Primer Is Best for You
The critical factor in choosing what primer to use with your rifle of choice is reliability. Small primers contain just enough primer to ignite a powder charge consistently when used under controlled conditions, such as with range or target shooting.
Large primers, by contrast, are designed to contain a powder charge that is large enough to work under all conditions. For this reason, a large rifle primer is usually preferred by hunters working in extreme cold or moisture.
When you consider the naming convention of primer sizing, it may seem obvious which one goes with your rifle. However, this is not always the case. Large rifle ammo does not always use large rifle primer. For example, many styles of 308 Winchester, a large rifle round, use small rifle primers.
To avoid running into any issues that can affect the functionality and accuracy of your rifle, it is always best to refer to the operators manual that comes with it.
Benefits and Differences of Small Rifle Primer Systems
One type of primer is the small rifle system. These rounds are made with a primer that is 0.175″ in diameter. As stated previously, small rifle primer systems are preferred for their reliability.
Small Rifle Primers use a heavier and thicker cup to withstand the high pressure exerted onto small-cased cartridges. The nomenclature between small and large primers can be deceiving. Small rifle primers are best for cartridges which require the highest pressure for effective ignition.
Boxer vs Berdan Priming Systems
Among small rifle ammunition, there are two different priming systems. These two parts are known as Boxer and Berdan primers, both named after their respective designers. It is crucial that these two types are not confused, as they are not interchangeable.
The difference between these two types is the placement of the anvil within the primer. The anvil is the hard point which crushes the priming compound, exerting the force needed to fire a round.
The Berdan system contains an anvil held separately from the primer itself, within the primer pocket on the cartridge. When the primer is seated, it is placed in proximity close enough to the anvil to ignite the powder charge when struck.
The Boxer system, by contrast, the anvil is separate from the cartridge, built into the primer itself.
Both primer types are able to be reloaded. However, due to Boxer primers’ single flash hole, they are much more efficient and simple to decap than Berdan primers. In order to reuse Berdan primers, you will likely even need special equipment.
Benefits and Differences of Large Rifle Primers
The other type of primer is the Large Rifle System, which come in a wider 0.210″ diameter, as opposed that of the small rifle primers. A large primer system is preferable when you are using difficult to ignite charges, or shooting in extreme cold.
Magnum Primers
For larger charges which use very slow-burning powder, a special class of primers was developed to ensure proper ignition. Magnum primers will create pressure much greater than a standard primer. However, it is important to remember that a case with a “Magnum” designation does not necessarily entail the use of a Magnum primer, so always be sure to refer to your user manual.
Bench Rest/Match Primers
These types of primers are often used by competitive or long-distance shooters, as they are designed to offer the most consistent results from one shot to the next. If you use a high number of rounds and need the most reliable results possible, especially under controlled conditions, this variety of primer can be a great option.
However, for most applications, a standard primer will be perfectly sufficient.
Size Variations Between Manufacturers
One last factor to consider when choosing your primers for reloading are the small, but often detectable differences resulting from manufacturer’s proprietary processes. This can result in reloading press jams, a frustrating issue for those who hand-reload. If you have this issue, simply try a different brand of primer until you find one that matches.
While this can be a bit of a laborious process, it is ultimately worth it to ensure consistent functionality from your rounds, and consequently that your time and effort spent reloading the rounds isn’t wasted.
Why Hand-Reload Your Rounds?
With concerning ammunition shortages and rising costs in nearly every model of round, looking for ways to reduce your costs can be a great option. One of the best ways to do so is by hand-reloading new or used rounds.
This process involves assembling a cartridge case, and adding a primer (choose this using what you’ve learned above!). Next, a powder charge is added to the case, and a bullet is set into the charge. If you find yourself using large amounts of ammunition and spending more than you’d like, consider learning how to reuse your spent cartridges.
Aside from being cost effective, building your own ammunition gives you greater control over how it fires according to your personal preference. Many people even enjoy doing this for their own enjoyment. All that you will need in order to do it is a small handful of supplies. Often, the supplies you need will come in prepared kits, making learning process easier than ever for a beginner.
Use Your Rifle With Confidence!
As you’ve learned, your choice of primer can have a great impact on your shooting experience. Now you can hit the range or venture on the hunt with confidence, knowing you’ve made an informed choice on what type to use with your rifle of choice.
If you’re interested in hand-reloading rounds for even greater control over your firearm’s functionality, Diamond K Brass has the materials you need! Specializing in premium quality primers and brass for a wide range of applications, Diamond K Brass is dedicated to providing the reloading community with the best materials available.
