(re)Loading Basic Operations

In the theme of keeping this whole blog about top to bottom reloading. It seems necessary to discuss the technology contained in most reloading die sets. While there is substantially more to making ammunition than just these simple die sets which you can buy for less than $100, the common set of reloading dies is the closest most people will get to the rest of the tooling.

Reloading procedures are fairly uncomplicated, and is usually summed up in 2-3 reloading dies, and 5-6 steps.  The basic steps of reloading should be summed up as: Decapping, Sizing or Re-Sizing, Expanding, Belling, Charging*, Seating, and Crimping.

Decapping is the operation which ejects the spent primer from the pocket, for boxer type cases, this is simply done with a rod with a pin on the end of it which knocks it out of the primer pocket.

Sizing is the operation which changes the external dimensions of the shell casing, pushing the brass back to the shape of an unfired shell. Or at least something resembling one.

Expanding comes in several forms depending on the style of the case. Bottlenecked cases (most rifle cases, EG .30-06) use a button that is typically part of the decapping rod that is pulled out of the case and brings the neck up to the proper diameter. On pistol and some straight-walled rifle cases (such as .357 Magnum, or .45-70) a plunger is inserted into the case mouth, the plunger usually has a conical section towards the top which also bells the case mouth, again, multiple operations in a single die.

Charging dies are usually fairly simple, and are designed simply to act as a station where a mechanical device such as a powder measure will dispense a set amount of powder into the case. They are really only used on progressive and turret presses. In certain circumstances, the powder funnel will have an expander and belling section on it as well, giving three operations in a single die.

Seating and Crimping are two operations which are usually performed by the same die, however, the best performance is gained by separating these two steps, running a seating die (which may also feed bullets) and a separate crimping die.  Seating, pushes the bullet into the case mouth, Crimping forces the case mouth into a grove around the bullet called a cannelure, making the now completed round of ammunition much stronger and more weather resistant.

For two die rifle sets, the Decapping, sizing, and expanding steps all occur in the first die.  In pistol sets, decapping and sizing are accomplished by the first die, requiring the second die to perform expanding and belling steps. In all cases of production reloading dies, the Seating and Crimping is performed on a single die, however, many companies make aftermarket crimping dies of differing designs which can overcome the limitations of the combined Seat/Crimp dies sold by most companies.

Reloading requires all of the operations covered here, and a few others which I will get into later. However, it is important to understand the difference between reloading and loading, as loading encompasses only the charging, seating and crimping operations. This difference greatly affects throughput when making ammunition.