Reloading Basics -  Dispensing powder charges

The amount of powder that goes into a round of ammunition is undoubtedly the most significant variable in reloading. Staying within the range between the start load and the maximum load stated in the reloading data you are using, will usually keep you safe, but the charge you use still needs very close attention. The accuracy and consistency of your dispensed powder charges are critical for precise and consistent ammunition.

Volume or weight
There are several ways of measuring powder charges and they all have advantages and disadvantages. Measuring powder charges by volume is probably the oldest method and it is certainly one of the quickest. Measuring them by weight is generally a slower method but it tends to be more accurate. The method that you choose needs to match your expectations, in terms of the amount of time you want to spend reloading and the degree of accuracy you want to achieve.

Powder charges by volume
A very simple ‘scoop’ with a known internal volume, either purchased or homemade, is a very fast way of measuring powder charges. You can look up the weight-to-volume data for a particular powder online and then work out the weight of the powder in your scoop (you still need to weigh and check a charge just to be sure). A homemade scoop can be adjusted so that it holds exactly the right amount of powder.  If you do use an improvised or homemade scoop, it is very important to ensure it is not made of a material that might cause a spark and ignite the powder. To get the best possible accuracy, you must level off the powder in the scoop consistently and carefully. Applying any downward pressure will compress more powder into the scoop and so increase the amount of powder that it contains.
The second method of powder measuring by volume is to use a measure that feeds powder into a cavity of known capacity, before dropping it into the case. Lee Precision’s Auto Disk Powder Measure comes with a set of disks which each have six cavities of different volumes cut into them, to measure powder charges of different weights. Their Deluxe Perfect Powder Measure uses a single but adjustable cavity to do the same job and allows you to set the chamber to hold exactly the right amount of powder. Hornady’s Lock-N-Load Powder Measure takes this to the next level, with highly engineered, adjustable, and interchangeable ‘metering inserts’, so you can have one set for each powder and charge weight that you use.
These powder measures drop the charge straight into the primed case, and most can be fitted to your progressive press to further speed things up. For producing a large number of rounds in pistol calibres relatively quickly, this type of tool, mounted onto a press, is a great option.

Powder charges by weight
Weighing each powder charge can be slow, but it is a method that gives you far more control over consistency. Balance-type scales are extremely accurate and although slow, they do give good results. Digital scales are very popular because they reset and zero much faster than balance scales, speeding up the process considerably. When you use a digital scale, the display will usually have an accuracy of +/- 0.1-grains, and you can hone the accuracy somewhat by using a method called ‘trickling-up’. If you put a slightly under-weight charge in the pan on the scale and then add the powder grain-by-grain, as soon as the display changes to the required weight, say 12.0 grains, you know that the actual weight has just entered the bottom end of the accuracy range, in this case, 11.95-grains. Once you get used to doing this, you will find your loads are much more consistent.
Although dispensing powder charges by weight has generally been a slow process until relatively recently, technology has now come to the rescue with electronic powder scales that both dispense and weigh the powder automatically. The Hornady Auto Charge Pro scale and dispenser is at the cutting edge of this technology. Although expensive, it is a significant step forward for those who weigh their charges. The powder is held in a large hopper and fed through to the pan on the scale automatically. The weight you require can be set and stored in the memory, and you can adjust the speed at which charges are dispensed. The slower the powder is discharged into the pan, the more accurate the weight will be. Each time you put the pan back onto the scale, the powder is discharged into it again. Accuracy is very good and very consistent, and this device really speeds things up.

Accuracy
Whichever method you choose, it is important to aim for as much accuracy as you can, while also matching the degree of quality control to the type of ammunition you are loading. Light loads for cowboy action shooting with an underlever rifle do not really need the same degree of consistency as loads for precision shooting at 300 yards with a target rifle.
A discrepancy of 0.1-grains on a powder charge of 40-grains represents just a quarter of one per cent, but that same discrepancy in a 10-grain charge is one per cent, which is more significant in terms of consistency. This is why you need to ensure that the degree of accuracy that you achieve will match your expectations in terms of results on the target.

Conclusion
When it comes to measuring powder charges, you can spend next to nothing and make your powder scoops, buy either a mid-range powder measure or a relatively cheap digital scale or go to town and buy a top-end, fully automated device. Whatever you use, it will have its own inherent level of accuracy and speed. The balance between these two factors varies and it is up to the individual shooter to decide for themselves which takes priority and satisfies their needs.