Reloading Basics: Ammunition Performance Checks

Once you start reloading and shooting your own ammunition there are likely to be a few ‘teething problems’ while you get used to your equipment and the reloading processes. No matter how much you read up on the subject, reloading is not a simple process and it is very much a case of ‘practice makes perfect’. One of the best ways to check you are getting it right, after test firing your ammunition, is to carry out a ‘post mortem’, including examining your gun and your targets.

The gun

Any effect on the gun due to significantly excessive powder charges will normally be very obvious immediately, with either the gun being damaged, or the action being very difficult or impossible to open. Likewise, a significantly light powder charge may well leave a bullet halfway up your barrel. If you do think you have damaged your gun, or have a bullet stuck up the barrel, a visit to a competent gunsmith is a must. There can, however, be more subtle indicators that will indicate a problem with your reloads.

When you are cleaning the barrel check the patches for signs of excessive leading, in extreme cases you may see tiny shards of lead on the dirty patches. A build-up of lead in the barrel will affect accuracy so if your group opens up after as few as 50 rounds, and a thorough clean of the gun brings about an instant improvement, then excessive leading is a likely cause. Bullet fit, hardness, velocity and lubesuitability for that velocity can all be causes of excessive leading. A simple change of bullet, from one brand to another, can often resolve these issues so it is well worth trying a different one.

The target

In an ideal world you will have a nice tight group of shots on your target, neat holes exactly where you wanted them, but this is not always the case. If there is no group at all, with shots all over the target, and you are happy that the gun and sights are set up properly, then it is likely that either the ammunition is not compatible with your gun, or your reloads have not been put together properly.

So, what is meant by ‘put together properly’? Correctly made ammunition will be of a consistent Cartridge Overall Length (C.O.L.), with the same powder charge, primer, case and crimp in each round. Applying exactly the same amount of pressure to the press for each round is also vital. If your target is disappointing it is worthwhile revisiting the press and tightening up on your practices.

It could be that your bullets are just not compatible with your gun. Sometimes, for a whole variety of reasons, you can get bullets that will simply not shoot well in a particular gun. They may well be the correct calibre, weight and type for the gun, but you just cannot get them to shoot a group. As an example, a particular brand of lead bullets might be either too hard or too soft to engage in the rifling of a barrel properly and so will not stabilise or obdurate correctly.

Another explanation can be that the bullets just do not fit the barrel. Bullet fit is a whole subject on its own but in simple terms, it has to fit the barrel sufficiently to fully engage with the rifling and keep the pressure and heat created by the powder charge behind it where it belongs. If these hot gases get around the bullet as it travels through the barrel then you will lose pressure, and therefore velocity, and the bullet will be damaged and so be less accurate.

Fly straight

Occasionally a target can include holes that show that bullets have hit it side on, rather than nose first. This is an indication that bullets are tumbling, having failed to stabilise correctly in flight. Although there are bullets that are specifically designed to tumble on impact with a soft target, causing a ‘keyhole’ effect on whatever is hit resulting in more damage, this is not a desirable effect for target shooting.

Tumbling is most often caused by the failure of the bullet and the bore of the gun to interact correctly and impart the desired spin on the bullet. Worn rifling, the wrong bullet for the rifle twist in the particular gun or the bullet not being the correct fit in the barrel can all cause the bullets to destabilise and tumble but there is also a cause that can be attributable to the reloads themselves.

The bullet needs to reach sufficient velocity in the barrel for the rifling to put the correct spin on it and give it what is called ‘gyroscopic stability’. If the powder charge is too light for the particular bullet it will not travel through the rifling fast enough to be stabilised and will quickly veer off target and start to tumble. During testing a specific powder charge fully stabilised a known brand of 158-grain semi-wadcutters, but when it was used behind home-cast bullets of the same weight and shape they tumbled. Such is the variance in the science of reloading. When the powder charge was increased by 0.2-grains the home-cast bullets stabilised and performed much better.

If bullets are tumbling a very small increase in the powder charge being used usually resolves the problem, or if the powder charge is already at near to maximum you can increase the crimp on the case. The tighter crimp will cause a small increase in pressure, the bullet is then dispatched with more velocity and this should result in better stability.

Conclusion

The above are just a few examples of what information can be gained from studying the targets and the gun, and how making minor changes to the reloads can improve their performance.

Reloading is a hobby in itself and the number of variants that have an impact on how your ammunition performs is sufficient to keep you looking for that ‘perfect load’ for all of your shooting life. Issues like bullets tumbling are a fairly easy fix, with a change of bullet or a tweak of the powder charge solving the problem quickly. Matching the twist of your rifle barrel to a bullet design and weight is now very simple, with a huge amount of information being available online and from manufacturers.

As always, the over-riding caveat is this, reloading data has been produced by the experts and you should always stay within the guidelines they issue. The loads they publish work in the test guns they use. If a load does not perform well in your particular gun by all means tweak the loads, but do not exceed the maximum powder charges. If you are experiencing issues with the accuracy of your reloads do not allow yourself to drift outside of the limits of the reloading data you are using in search of the perfect load, safety first, accuracy second!