Small arms primers contain an initiating explosive mixture. By design, this explosive is easily initiated by impact energy. Two key safety issues with primers are dusting and mass detonation.

“Dusting” is the term describing minute particles of the primer explosive mix. The dust from a primer contains the same initiating and explosive qualities of the primer itself, including initiating sensitivity to friction (impact). At the time of manufacture, the explosive mixture of the primer has a binding ingredient. After manufacture, handling of the primer can result in some of the mixture breaking apart, forming explosive dust. Over time the primer dust can form a thin layer in and around the handling and storage areas of primers. Friction or spark can initiate the dust. Proper cleaning is the best way to avoid a problem.

A mass quantity of primers loose in a container can detonate with the power of the total explosive quantity of the individual primers. If an initiating force ignites just one primer, the explosive energy can create a “mass detonation” of all the primers.

When primers are manufactured, they are placed directly into packaging designed to prevent propagation and mass detonation. Always store primers in their original containers. When reloading, limit the quantity of primers you remove from the factory packaging.


Reloading ammunition is a great hobby and saves money. Commodity cost increases in brass and lead in recent years have resulted in many new and/or returning reloaders trying to stretch their budget.

The following information is provided as an introduction on the stability, storage, and safe handling of modern smokeless propellant.

Smokeless Propellant

The main ingredient of smokeless propellant, comprising from about 55% to 90% of the composition, is nitrocellulose. The process of creating nitrocellulose leaves remnant acid in the material. This acid immediately starts decomposing the finished product. Left alone the decomposition will reach the stage where the propellant becomes unstable and self-ignites. This process resulted in massive explosions at U.S. Government arsenals after World War I.

To increase the life of the smokeless propellant, a stabilizing chemical is used. This “stabilizer” reacts with the acid to slow down the decomposition process. However, as the stabilizer reacts with the acid it is consumed. After the stabilizer is totally consumed, the propellant is no longer protected from the internal acid.

The entire stabilizer / decomposition process is a time and temperature function – the higher the temperature, the shorter the safe life of the powder. Even moderate temperature, over extended time, leads to propellant decomposition. As a rule of thumb, any temperature over that which is comfortable to a person is accelerating the decomposition of smokeless propellants.

Under proper storage, modern smokeless powder can last for decades. However, this does not mean the reloader can ignore how the powder is stored, particularly if in an uncontrolled environment such as a garage or storage building.


Hodgdon reloading data shows starting loads and maximum loads. You might have heard a fellow reloader claim that published reload data errs on the low side and it is OK to exceed maximum charge recommendations. THIS IS NOT TRUE – and is why Hodgdon publishes pressures with all its reloading data. The MAX load pressures shown by Hodgdon match the industry standards, just as the ammunition loading companies do in factory loads. There is a reason why this is called a MAX load – because it is! Trying to push your reload any stronger exceeds the design limits of the ammunition components and gun.


It seems the more you enjoy handloading, the more clutter starts to find its way on your reloading bench. No matter how cluttered your reloading area gets, there is one simple tip that will keep it fun and safe:

Have only one powder on the bench at a time.

There are enough things to do while reloading – so why complicate things? Having only one powder on your bench while reloading prevents accidental use of the wrong powder or mixing of powders.


If you reload and shoot multiple caliber firearms, be aware of unsafe firearm and ammunition combinations. Avid reloaders and shooters often head out to the range with multiple calibers of firearms. It is very easy to grab the wrong caliber and insert it into the gun. If the caliber just does not fit, this is simply embarrassing. Although in some combinations, loading the wrong caliber into the gun can have dire consequences.

Most shotgun shooters are aware of the danger of inserting a 20-gauge shotshell into a 12-gauge gun. The 20-gauge shotshell will lodge in the throat, leaving enough space behind it for a normal 12-gauge to load and fire. This situation will usually destroy the gun and can injure the shooter and/or bystanders. This is the reason American shotgun shell manufacturers reserve the hull color yellow for 20-gauge shells only.

But this is not the only unsafe gun and ammunition combination. The Sporting Arms and Ammunition Manufacturers Institute (S.A.A.M.I.) maintains a list of all unsafe firearm and ammunition combinations on its website. It is well worth looking at this list.


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