The information on this page is only meant to give brief information on what is involved in re-loading centrefire ammunition. You should follow the instructions that come with your re-loading equipment, and preferably buy a good reloading manual on the subject. (MPCI will not be responsible for overloading, incorrect storage or improper resulting in personal injury or death to the user and/or other persons as well as damage to property.)
Handloading Safety Rules.
Before you get started, read these safety rules and memorise them.
Cartridge brass is carefully tempered in its final manufacture. The head of the case is thick and tough which gives it the strength and rigidity necessary to resist the force of the chamber pressure. The forward section of the case (neck, shoulder and body) is considerably thinner than the head section. In manufacture, these portions are given an anneal which leaves them soft and ductile. The obvious advantage is that the case walls and neck will now expand freely to release the bullet and seal the chamber while the cartridge is fired.
As shooters, we may have been rather casual in our regard for empty brass cases, but as reloaders we soon come to think differently. Without a quantity of strong and serviceable cases, we would not get far in reloading ammunition. The reloader may purchase new cases from his component dealer.
To make sure your cases are in prime condition, start with either new or once-fired cases. Never use brass of unknown origin such as that found on a shooting range.
Each firing and resizing has an influence on the serviceability of the case. The battering of chamber pressure and the forces applied by the resizing die eventually work-harden the forward portion of the case and destroy its usefulness.
Carefully inspect your cases before each reloading. If your cases are new, or once fired, they will not reveal fatigue at the first reloading. However, fatigue signs will show up in subsequent loading, so you must learn to look for them.
Check your cases for splits or cracks in the neck, shoulder or body. Reject all cases that show signs of defects, but flatten them with a pair of pliers before discarding to prevent their reuse. We suggest you separate your cartridge cases into lots and keep a record of their history.
Trimming is necessary when your cases have lengthened after numerous firings. Check your cases after resizing and never allow them to exceed the maximum listed measurement. How often you will need to trim the cases depends largely on the type of case you are using and the pressure of the load. Bottle-neck cases take more abuse from pressure than straight sided cases and require trimming more often. The trimming of any case more than four times is not recommended. After this amount of trimming, it may be assumed that the case walls are now too thin, and the case should be discarded.
Many people are concerned with the dangers of handling and loading modern smokeless powders. To the uninitiated, gun powder is often regarded as "explosive"-something to be feared such as dynamite. This is quite a natural presumption.
The various modern powders used in reloading are classified as propellants, which means they are chemical mixtures designed to burn under controlled conditions, and to propel a shot charge or projectile. A high explosive, on the other hand, is a completely different breed of cat. These mixtures are quite dangerous because they are designed to detonate. When a substance such as dynamite or blasting gelatin is detonated, it produces intense heat and violent shock waves. These shock waves exert tremendous pressure on anything they contact, which makes it almost impossible to vent away the effects of detonation involving any appreciable quantity of explosive material.
While not to be compared to explosives, modern reloading powders are nonetheless highly flammable. They not only burn, they burn vigorously. In case of accidental ignition, a great amount of gas at high temperature will be formed. If the powder is stored in its original factory canister, as it should be, this gas will create a pressure on the relatively fragile sides of the can. The pressure will split open the seams of the container, or pop off the lid. In such an event, the pressure remains at a low level if sufficient space is provided to accommodate the escaping gas and vent it away.
For safe reloading, large quantities of reloading powder should never be stockpiled. The few cans that you do store must be handled with the care and caution due a flammable substance. In this way you control the situation so that it cannot get out of hand. Even in the case of a total house fire arising from other sources, smokeless powders will not produce the effect of an explosion if the proper precautions have been taken.
The burning characteristics of smokeless powders are complex in nature and, depending on the application of the powder, their burning rate can change drastically. While the chemical composition of a powder, the shape and size of its particles and the density or porosity of the powder composition, tend to control burning rate, the application of each powder must be carefully considered. Other conditions such as the degree of confinement, the heat of ignition, the temperature of the combustion chamber, the chamber pressure, and the density of loading, all affect the burning rate, yet such vital factors cannot possibly be included in the so called burning rate charts.
All reloading powders are manufactured to an exacting set of specifications. They are sold in factory sealed canisters with the name, or number, of each specific powder clearly printed on the label. When you purchase a reloading powder, you can be sure of obtaining the exact powder specified, and that the contents of the can have not been tampered with.
When weighing a powder charge, you depend on the accuracy of your powder scale and, of course, care must be taken. Reloading scales are designed specifically for the weighing of powders. These scales have a guaranteed accuracy of one-tenth of a grain, which is more than adequate for the most demanding reloading requirement.
NOTE: This chapter refers only to rifle and pistol cartridge primers.
For a cartridge to function properly, the successful operation of each component is required. Primarily from a safety standpoint, we have stated that the cartridge case is the most important component. However, if a primer does not ignite, we will have a misfire and all of our concern for case inspection, powder selection, etc., will be for naught. Therefore, every component, including the primer, is critical to the performance of the load.
Actually, the primer is responsible for only a small percentage of the accuracy of a given load, but its burning characteristics will add or detract from the overall pressure. How much these burning characteristics affect pressure is relative. It depends primarily upon the application of a specific primer to a specific set of conditions. Generally, the primer's influence on pressure is minimal when compared to the possible effects of other conditions and components. This influence, however, is not so slight that it can be overlooked.
In testing metallic cartridges pressure variations (due to primer change) of approximately 2,000 C.U.P. have been noted. Further testing could indicate still greater variations. The point is that while metallic cartridge primers do not seem to vary greatly, enough variation exists to require us to re-work a load when changing primer type or brand. The reloader should stick with the same brand and type of primer when working up and using a load. If he changes the primer brand or type, he must then go back to the "starting load" and begin again.
If you examine a "Boxer Type" primer carefully, you will note that the anvil protrudes slightly beyond the end of the primer cup. This is not an oversight in manufacture! The anvil is supposed to protrude so that it will seat solidly against the bottom of the primer pocket and firmly resist the force of the firing pin blow. If the primer is seated incorrectly (leaving space between anvil and bottom of pocket) then the entire primer will move forward when struck by the firing pin. Such a condition retards the blow of the firing pin and causes inconsistent ignition.
When seating primers, make sure that the primer bottoms in the primer pocket. However, the primer should not be crushed. Normally, when a primer is seated correctly, it will be flush with the head of the case, or perhaps a few thousandths below. Under no circumstances should the primer stick out beyond the case head. Such a condition can prove dangerous particularly in auto loading firearms, for the primer is in an exposed position. If such an improperly seated primer were to receive a blow from the bolt face, it could fire before the round was safely chambered.
Boxer primers having either round or flat dome construction may be encountered and the correctly shaped priming punch is available for either contour. Use the flat punch for the flat primer and the concave punch for the round primer. Before seating a primer it is wise to examine it visually to make sure the anvil is not missing. Although this rarely occurs, the resultant misfire could be embarrassing if it should come at the wrong moment.
A word of caution on handling primers. Primers are detonated by percussion (a sharp blow). As packaged by the manufacturer, primers are quite safe, but they should not be tossed about or handled in a careless manner. Keep your primers in the factory container until they are to be used. Never store primers in a makeshift container. An old glass jar full of primers could become lethal if dropped or accidentally knocked onto the floor.
Some military cases are loaded in a manner which employs a slight crimp over the primer to hold it snugly in place. These cases can be de-capped without difficulty, but the crimp must be removed before the case can be primed again. Various commercial tools are available to do this job. Primer pocket reamers come in two sizes, large and small.
One last thought, never de-cap live primers. If for some reason live ammunition must be disassembled, pull the bullet, pour out the powder, chamber the primed case in a firearm, and snap the primer before de-capping.
Today's metallic reloader uses, primarily, jacketed bullets. These copper clad projectiles are far better performers, in all but a very few applications, than are bullets cast of lead alloy. Since jacketed bullets are the most popular, we'll limit our discussion to that type although the same principles also apply to cast bullets.
There are several factors to consider when selecting a bullet besides having carefully tested load data for a given projectile weight:
There are only six basic mechanical operations required to reload a cartridge. Four of them are performed by the reloading dies.
Now, if your cases have been properly inspected and you've selected a load, and purchased the necessary components (primers, powder and bullets), you are ready to begin.