Small adjustments to your reloading process
- Last updated: 12/12/2024
If you compare modern reloading dies to what was available some 50 or 60 years ago, you can see they have come a long way, with the older tools being far more basic. They still work fine and will produce useable ammunition, but compared to the more refined tools of today, they are somewhat lacking in finesse and adjustability.
We now have ‘micro’ adjustability on many reloading tools, but what does this mean for the average home-loader? The word micro means ‘extremely small’, and for those that make ammunition, that means measurements in thousandths of an inch and tenths of a grain. The effects of making micro adjustments are well worth exploring, and if you have equipment that has this fine level of adjustment built-in, it is something that you should experiment with. It might just make a significant difference to your ammunition.
Case resizing
Full-length case resizing is not generally something that can be adjusted. However, if you neck-only resize, it is possible to use interchangeable collets that vary in size by just one-thousandth of an inch. By measuring the diameter of your bullet and the thickness of your case at the mouth, you can work out the best collet size to make your cases grip your bullet correctly. If you then acquire additional collets that are larger and smaller in diameter than the calculated best fit, you can both increase and decrease neck tension. More neck tension means more grip and therefore more chamber pressure. Less tension means less grip and reduced chamber pressure. It is crucial to apply the right amount of tension when loading the bullet into the case in order to prevent slippage.
Bullet seating
Micrometre adjustable bullet seating dies are available from most manufacturers as part of a set or as an individual addition. The Hornady Match Grade Die set, for example, includes their micrometre adjustable seating die. Being able to make micro-adjustments to the cartridge’s overall length (COL) allows you to experiment with making ammunition slightly longer or slightly shorter than the COL stated in the reloading data you are using (within safe and reasonable limits), and this can be one of the most significant changes you can make.
With very high quality and well-engineered bullet seating dies available, it is now possible to make accurate and real 1/1000th of an inch adjustments more precisely and consistently than ever. The dies show absolutely no play or movement once set and the tolerances, compared to the dies available 50 years ago, mean that homemade ammunition can be the best it has ever been.
The COL affects a number of variables. The distance that the bullet travels before it hits the rifling in the barrel (the bullet jump), the amount of space left within the case (dictating the load density and therefore chamber pressure), and the amount of the bullet gripped by the case mouth (affecting chamber pressure) are all affected.
Adjusting the COL by two or three-thousandths of an inch above or below the published length can yield surprising changes in muzzle velocity and grouping on target.
Powder measures
Modern technology has allowed powder measures to be made more accurate and precise than ever before, with tools having charge cavities made of either plastics or metal to extremely close tolerances. The Hornady Lock-N-Load Powder measure has interchangeable metering inserts with variable capacities that can be adjusted by the very tiniest amount by turning the plunger. The Lee Precision Auto Drum Powder Measure has a key-operated adjustment system that allows you to change the charge weight by just a tenth of a grain at a time. These modern and very accurate powder measures allow you to play with powder charges by the very smallest of amounts and this can help you find the most near-perfect charge for your loads.
Also adjustable
The overall ‘straightness’ of your ammunition is very important, with everything from the primer and the case to the bullet and the bore. They all contribute to setting your bullets on their way straight and true. While many bullet seating dies centre the projectile by floating it above the case mouth before seating, there is still scope for improvement. Equipment like Hornady’s Lock-n-Load Concentricity Tool can identify, measure, and eliminate bullet run-out by pushing the bullet into the correct alignment. Alignment variances of just a couple of thousandths of an inch can be corrected, resulting in more consistent ammunition.
Tiny steps made one at a time
The ability to make micro-adjustments to reloads is a real gift and it means that you can experiment with endless combinations, remembering to stay within safe limits. The most important thing to remember is to only change one variable at a time. If you alter neck tension, COL, and/or the powder charge all at once, how will you know the effect that each one has had on your finished ammunition? You need to make a set of rounds with different COLs, a set with different neck tensions, and then one with varying powder charges. After that, you can combine the best of each group or try several different combinations. Although the search can be endless, you can experiment until you cannot improve on your ammunition anymore. This comes with a word of warning, as the search for the holy grail of ammunition can occupy a lifetime of reloading!
Conclusion
Being able to make such small adjustments to reloaded ammunition allows you to both experiment with different aspects of the process and also to overcome any irregularities in the components you are using. If some cases have thicker brass at the neck than others, you can change the collet in your neck-sizing die accordingly and ensure that the neck tension is the same as with the thinner-walled cases. This is just one example of why micro-adjustable reloading tools are well worth using.