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Reloading Basics: How to Read Powder Scales Accurately

  • Last updated: 03/10/2025
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Reloading Basics: How to Read Powder Scales Accurately

Reloading your own ammunition provides a useful blend of cost-effectiveness and customisation, but a crucial aspect of safe and accurate reloading is the ability to read and interpret powder measures with precision. Even small inconsistencies in how a measurement is read can cause significant variations in muzzle velocity and trajectory, which in turn affect accuracy and the point of impact.


A typical ammunition reloading setup on a workbench.

Why is an accurate powder charge so critical?

A good-quality and reliable powder measure, whether volumetric, weight-based, or electronic, is an essential tool in the reloading process. It ensures consistent and accurate dispensing of powder, which directly influences the ammunition’s performance. Depending on the type of measure, you need to read the display, scale, or setting the same way each and every time to ensure the charges dispensed are consistent and accurate.

Inaccurate powder charges can cause dangerously high chamber pressures if too much powder is used, or underpowered rounds if too little is used, in which case the bullet may lack the energy to exit the barrel and instead become lodged in the rifling. Both can be dangerous. Overpressure can damage the firearm and potentially injure the shooter, and underpowered rounds that leave a bullet stuck in the barrel are very dangerous if they go unnoticed and another round is fired into the blocked barrel.

Consistent powder charges are essential to maintain uniform muzzle velocities, which in turn are required for tight groupings and reliable accuracy, especially at longer ranges.

How do you read different types of powder measures?

Volumetric powder measures are generally set up once to discharge the required powder charge when they are cycled, and they do not require reading each time powder is discharged. The critical thing with this type of measure is to ensure it is set up correctly at the start and that it does not slip out of adjustment. A weighing scale is usually used to check the amount of powder being discharged by this type of powder measure, and you should check several charges to ensure that the correct amount is being discharged and that it is consistent. Weighing up to 20 charges may be necessary to ensure that the correct amount of powder is discharged each and every time.



Volumetric measures need to be set and checked using a set of scales.

Some powder measures that dispense by volume have adjustable cavities that hold the powder charge, and it is very important to ensure that, once set, they are locked in position so they cannot creep out of adjustment. Putting marks on the adjuster and the body of the powder measure can help ensure that any slippage can be seen and corrected.



High-quality volumetric powder measures from Lee Precision and Hornady.



Locking rings on Hornady’s Lock-N-Load powder measure metering inserts prevent them from creeping out of adjustment.

Weight-based powder measures generally give greater accuracy by dispensing powder by weight rather than volume, and they are read each time a powder charge is dispensed. They are less affected by factors like powder density and inconsistencies. This type of measure requires you to read the weight, either on a digital display or via the markings on a beam-type scale. Reading these scales correctly is vital for producing consistent ammunition.

It might seem very simple to read a weight on a digital display, but there is actually a lot more to it. This type of scale generally displays weights to one-tenth of a grain accuracy on the screen. It can take the scale a few seconds to settle and show the correct weight. When the weight on the screen fluctuates between two readings, for example, 11.9gr and 12.0gr, it is showing that the weight is close to the border between the two weights and its inbuilt degree of accuracy is compromised. This is actually an opportunity to enhance the consistency of your ammunition, and you can trickle tiny amounts of powder onto the scale until, in the example above, it just stabilises at 12.0gr on the screen. This process, called trickling-up, results in powder charges that are all at one end of the scale’s inbuilt accuracy, and in this example, they are all at the lower end of the range between 11.95gr and 12.05gr. This fine-tuning of powder weights can greatly improve the accuracy of your ammunition.



Trickling-up powder charges will improve accuracy and consistency.

Mechanical beam scales, like the Lee Safety Scale, can also achieve good accuracy and consistency provided that you read them properly. These scales rely on you being able to read exactly when the pointer on the scale body is aligned with the indicator on the beam. This can take a lot of practice, and you can ‘enhance’ the scale by adding an even finer marker to align with the indicator. Once you get used to reading the scale in a particular way and stick to that way, you will produce consistent powder charges.



The Lee Safety Scale is an excellent beam-type scale, and it is easy to read.



Detail of an enhanced marker on a beam scale, designed to make reading more accurate.

What other factors affect consistency?

Whichever powder measure type you use, it must be set up correctly and securely placed on a level surface free from vibration or movement. With particularly sensitive powder measures, placed on a table on a timber floor, how close you stand to the measure, or leaning any weight on the table, can cause the display to alter as the floor or table moves. It is important to stand in the same position when measuring powder charges and not lean on the table.

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All scales should be calibrated regularly. They normally come with instructions on how to do this, and if you have more than one set of scales, it is also worthwhile checking them against each other regularly.

With beam-type scales, positioning the scale at eye level so that the markings are viewed straight on, rather than from above, allows for a more comfortable and accurate reading of the pointer and helps achieve greater consistency.



Beam-type scales need to be at eye level so that they can be read accurately.

Check-weighing charges regularly, perhaps every 5 or 10 rounds, is a good way of confirming that your powder charges are consistent and that nothing is moving out of adjustment.

What is the conclusion?

By mastering the art of reading your powder measure accurately, you can ensure the safe, efficient, and precise production of consistent ammunition. The equipment available nowadays is very accurate and more than capable of giving the required level of consistency, but it is very much dependent on the user ensuring that they read it with care.

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