How to choose the right powder for reloading ammunition?
Reloading ammunition is an exciting discipline that allows you to optimize ballistic performance according to the shooter's needs. The choice of reloading powder is a crucial decision that directly influences the safety, accuracy, and consistency of shots. Choosing a powder that is appropriate for the caliber, projectile, and objective is a very important element in the performance of your ammunition.
1. The liveliness of the reloading powder
The liveliness of a powder refers to its combustion speed. It is decisive for the pressure developed in the chamber and the acceleration of the projectile. A general distinction is made between:
- Live powders : suitable for calibers with low powder capacity and handguns. Or for calibers with large projectiles relative to the powder volume (9.3x62, etc.)
- Slow powders : used for calibers with high powder capacity, such as very large caliber ammunition or ammunition with a low projectile diameter to powder volume ratio (a small bullet pushed by a lot of powder)
Choosing an unsuitable liveliness can cause dangerous overpressures or, on the contrary, too little pressure to create a seal in the chamber and therefore gas returns!
Attached is a table that allows you to compare the liveliness of a powder from one manufacturer to another. The liveliest powders are at the top of the table, the slowest at the bottom of the table (source: LINK)
Caution! Even if the liveliness is similar, do not duplicate a load by switching from one brand to another; you will have to start your load ladder again.
2. Single or double base powder for reloading ammunition
Ammunition reloading powders fall into two broad categories:
Single-base powders : composed primarily of nitrocellulose. They are often used for sport shooting ammunition and offer better thermal stability.
Double base powders : containing nitroglycerin in addition to nitrocellulose, they generate more energy and are often used for high-performance calibers, they are more aggressive on barrels and have less good temperature stability.
How can you recognize them? Each manufacturer has its own technical data sheet where the information is listed.
For some manufacturers, such as Vithavuori for example, powders beginning with the number 5 are double bases, those beginning with 1 are single bases.
3. Regularity of speeds as a function of temperature
Some reloading powders are more sensitive to temperature variations than others. A thermally stable powder guarantees consistent performance, regardless of the season, your muzzle velocity is little or not affected by the temperature of the ammunition. For long-range shooting or hunting in varied conditions, it is recommended to favor powders designed to offer little variation in velocity depending on the ambient temperature.
If speed is a key element that requires you to use double base powder, you will need to characterize the regularity of your speeds according to the temperature. For this, there are procedures visible here: Video of the test
4. Availability and compatibility of reloading powders
In the European market, several brands of reloading powders stand out for their presence and reputation among sport shooters and hunters. Here is a list of the main brands:
Vihtavuori : Originating from Finland, Vihtavuori is renowned for the consistency of its powder formulations, providing efficiency and accuracy for reloading. Their range covers a wide range of uses, from handguns to shotguns, including large caliber long-range (TLD) rifles, with powders specially designed to optimize the consistency of muzzle velocities and limit gun fouling.
Reload Swiss RS® : This Swiss brand, developed by Nitrochemie Wimmis AG, is known for offering the highest output speeds, however our tests revealed less stability to temperature variations than Vithavuori
These brands are widely available in Europe and are recognized for the quality of their products, meeting the requirements of ammunition reloading enthusiasts.
5. Fouling and combustion of reloading powders
Some powders leave more residue after combustion, which can affect how often the weapon needs cleaning. Clean-burning powder can extend barrel life and improve shot consistency.
During combustion, a deposit builds up in the chamber at the end of the collar, creating an extremely hard carbon ring that can cause a crimping phenomenon on the ammunition insertion. This phenomenon is known in the English-speaking world as carbon ring. Some powders are more prone to this problem.
Conclusion
Choosing a powder for reloading ammunition must be done carefully, taking into account liveliness, chemical composition, thermal stability, and compatibility with the weapon and caliber. By following manufacturers' recommendations and scrupulously adhering to reloading tables, it is possible to optimize the accuracy and safety of shots. For any ammunition reloading enthusiast, choosing the right reloading powder is a key step in achieving optimal performance.