RELOADING BASICS – The Powder Charge

Edit Content

AFFILIATE LINKS

When I make a product recommendation, the quality of that product is my first consideration. I will never recommend a product to you based solely on my financial interest in making the recommendation.

 

But, when possible, I will use affiliate links when sharing quality products in order to monetize the website. If a manufacturer I recommend does not offer affiliate marketing, I always link directly to their website. When you use these affiliate links, I receive a small commission on the sale. These links do not increase your cost on any item.

 

Currently, Newgrange Precision and its publications use the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for website owners to earn advertising fees by advertising and linking to amazon.com, audible.com, and any other website that may be affiliated with Amazon Service LLC Associates Program.

With your case preparation complete, you can now charge your case with powder. The process by which this task is completed is simple. Either the case or a powder pan is held under the drop tube of your powder thrower. The lever is actuated, dropping powder into its receptacle. If powder was dropped into a pan, that powder can then be weighed on a scale of dropped into a case via a funnel.

But determining which powder to use and the volume of powder to charge depends on a number of factors.

This guide is a work in progress. For the overview and links to other chapters, click here.

Powder Selection

Powder types are broadly categorized as being formed in the shape of a ball, a flake, or an extruded stick. Flake and extruded powders are inherently more difficult to meter consistently, as they don’t settle as evenly as spherical powder, and the powder thrower must “cut” some of the powder as the drum is turned. You will feel more resistance during the charging process as this cutting takes place.

Burn Rate

Powder burn is a function of surface area. If surface area increases as combustion takes place, burn rate climbs slowly toward a peak before dropping off. This is what you see with the extruded (or perforated, cylindrical) powders. Conversely, if surface area decreases as in spherical powders, burn is at its peak at ignition and then drops throughout the burn.

The pressure curve produced by a fast powder is typically steep, with peak pressure reached early in the pressure curve, whereas slower powders reach the peak later in the burn cycle. This is why fast powders are generally preferred for pistol applications and slower powders for rifle applications. The amount of barrel length available to reach peak pressure is shorter in pistols and therefore fast powders help minimize wasted, unburnt powder, while slow powders take full advantage of the barrel length available to them in rifle applications.

Temperature Sensitivity

Some powders will produce greater variation of velocity as the temperature changes. Obviously, choosing a powder that attempts to mitigate this becomes more important if your environment experiences broad swings in temperature between its extreme warm and cold seasons.

Measures and Tricklers

Powder measures and scales were briefly discussed in the chapter on basic tooling. The powder measure on a progressive press will automatically throw the charge as the press is actuated, whereas the powder thrower when using a single stage or turret press will be a separate assembly.

The bulk (or entirety) of the charge is thrown with the measure. A trickler can then be used to add very small, controlled amounts of powder to bring a charge weight up to an exact amount.

Weighing Charges

If you’re loading on a progressive press, you may want to check the weight of every powder charge until you feel satisfied with any variation in the thrown weight. After that, you may check at predetermined intervals as an ongoing quality check.

On single stage presses, especially on loads where you’re chasing low standard deviation and extreme spread, you might under charge each load and then use a trickler to get up to the exact same weight to reduce charge variability to near zero. This is a time consuming process, but will produce charges more consistent than factory ammo.

Storage

Powder should be stored in a cool, dry place. It should not be exposed to sunlight or any sources of heat such as furnaces and boilers, open flames, etc. Do not keep it in the same place as any solvents or other flammable materials.

Do not transfer the powder from an approved container to one which isn’t. Their factory containers are designed to open under pressure to prevent any dangerous pressure spikes should the powder ignite.

You should empty the hopper of your powder thrower after every session and return the powder to its container. If the powder attracts (or loses) water from the air, it can change the chemistry of the powder, affect its burn rate, and impact the resultant pressure curve.

Signs of Deterioration

You should get familiar with the normal smell of your powder. Powder that is breaking down will have an unpleasant smell that should immediately seem abnormal to an experienced reloader.

Deterioration is uncommon with modern powder under proper storage conditions, but be aware that it can happen. Once the reaction begins, it can accelerate and can even eventually cause spontaneous combustion. Immediately dispose of any suspect powder by burning out in the open in small quantities.

To return to the guide’s Table of Contents, click here.

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top