It may seem like a silly question, but hey, we have to start somewhere. Perhaps the best way to understand the reloading process is to consider what happens when we actually fire a centre-fire round. In essence, reloading is reversing this process.
A centre-fire round contains four basic components; namely the case, a projectile, gunpowder and a primer. Figure 1. When a round is fired, the firing pin of the firearm strikes the primer which is located in the centre of the base of the case. Hence, centre-fire round. The primer contains a small explosive charge which emits an intense flash through a small hole in the base of the case called the “flash hole”. In doing this, the primer is effectively destroyed by the physical impact of the firing pin and the resulting ignition of the explosive material in the primer.
The flash from the primer ignites the gunpowder in the case, converting the gunpowder into a hot gas which quickly expands to create a high pressure (as high as 35,000 psi). This hot gas not only heats and expands the case, but expels the projectile from the case at high velocity; commonly 800-1200 feet per second, but can be double or even triple this for large caliber magnum pistol or long arm loads.
After the projectile leaves the firearm we are left with a distorted, hot, dirty case, no gunpowder, a non-functional primer and no projectile.
So, in reloading we need to:
- Clean and resize the case back to a serviceable size
- Remove the expended primer and replace it with a new primer
- Replace the gunpowder
- Replace the projectile and crimp it into the case
In addition, longer cases such as rifle calibers may expand in length, and hence need to be trimmed back to the correct length before reloading. This is best judged using a set of digital calipers to check the case length against the case length specifications in a set of reloading tables. As my focus is on reloading for pistols, and in my experience common pistol caliber cases don’t expand in length to any significant extent, I won’t discuss the case length trimming process any further. If your primary interest is reloading for rifle calibers, I suggest a good reloading manual specializing in rifle ammunition as a good place to look for case trimming procedures and equipment.
Whilst factory ammunition comes in various types of cases, only good quality brass cases can be reloaded, and then only a limited number of times. Each time a round is fired, the case expands under pressure, especially around the case mouth where the projectile is held. During reloading, the entire case is compressed back into shape and size, and the crimp compresses the case mouth to hold the projectile in place. This repetitive expansion and compression causes metal fatigue, particularly around the case mouth. Eventually the case mouth will split, see Figure 2, and this marks the end of the service life of that case. i.e. it is now scrap value. The condition of the case, especially the case mouth, needs to be checked each time before it is reloaded. I find the best way to do this is to rotate the case with the case mouth between the thumb and forefinger, Figure 3. The tactile senses in the finger tips are very good at feeling any split in the case mouth. This takes bit of practice, but is often more effective than visual inspection of the case. In practice I have found that cases can be reloaded between 10 and 20 times. This depends a lot on the quality of the original cases and how “hot” your loads are.
At the end of the reloading process, you should have a nice bright, shiny round of ammunition which will work well in your firearm, and cost around half the price of a new factory round.
In the next article I will discuss the various reasons why you may want to reload your own ammunition. It certainly isn’t for everyone, but it can be a rewarding and cost saving addition to your shooting skills.
Featured image of once fired brass courtesy of Best Reloading Brass via amazon.com