Reloading Unlisted Bullets

While powder manufacturers will list reloading data for most of the bullets available today, and some bullet manufacturers also provide data for their projectiles, there can be times when you cannot find data for a specific bullet brand, type, and weight. If this happens, you must approach reloading these bullets with caution. You cannot simply use published data for a ‘similar’ bullet of the same weight and expect to get the same velocity and chamber pressure, that just does not happen.

The variables
Bullets of the same weight and diameter, but from different manufacturers, can differ in several ways, impacting how the bullet performs when incorporated into reloaded ammunition.
Even if the weight of a bullet is the same, the shape can vary considerably because of flat bases, boat tails, long or short ogives, hollow points, soft points etc. The list is endless, and these factors will all have an effect on the overall length of the bullet, while the weight stays the same.
The bullet’s construction and the materials used will affect the density, meaning it will act differently when subjected to chamber pressure and friction from the rifling. The copper used in jackets and the lead alloys used in the cores can also vary from manufacturer to manufacturer, with different thicknesses and hardnesses affecting how the bullets obturate.

The effects
When bullets of the same weight and diameter vary in terms of design and construction, they will behave differently in the rifle barrel. Softer projectiles, such as copper-jacketed lead-cored bullets, will obturate easier than solid copper alternatives and require less chamber pressure to force them into the rifling. Those harder bullets can require significantly more chamber pressure to get them to travel through the rifling and stabilise in flight.
Longer bullets can affect your reloads in two ways. So, for example, if you accommodate a longer bullet by increasing the cartridge’s overall length, you may find that the bullet hits the rifling in the barrel when it is chambered. The lands and grooves will grip the bullet and when the round is fired, this grip will resist the bullet’s path forward, increasing chamber pressure. Changes in bullet length will also affect bullet jump, which is another critical factor. If you keep the cartridge’s overall length the same, and seat the extra bullet length inside the case, then you decrease the amount of free space inside the case, increasing the load density. Changes in load density will also affect chamber pressure, and you may even risk compressing the powder charge, leaving no free space and increasing that pressure beyond the safe level.

The solutions
In order to find a safe load for an unlisted bullet, you must exclude as many of the variables as possible. For example, if you are using an unlisted solid copper bullet then you must immediately dismiss any data for softer, lead-cored bullets.
A critical factor when comparing projectiles is the bearing surface of the bullet on the rifling, as this will dictate how much friction is created, which affects chamber pressure. Measuring the entire bearing surface of different bullets can be hard, but there is a relatively easy way to do a comparison between two different projectiles. If you colour the entire surface of a bullet with a marker pen and then rub the bullet on a hard surface, the ink will only be rubbed off where the bullet and the hard surface meet, displaying the bearing surface. You can then measure the length of the rubbed-off area and compare it between the different bullets. If your bullet has a bearing surface that is larger than the one that you have reloading data for, then it will increase the chamber pressure, meaning it cannot be loaded over the same powder charge.
Having discarded the data for bullets showing a different construction and materials, and having ensured that the bearing surface is similar or certainly not greater with your unlisted bullet, then you should consider the bullet design, including the type of tip and base, and the length, then see if you can find something similar. The tip and base affect the overall length of the bullet, and you should look for as close a match as possible.
Unfortunately, bullet manufacturers do not always list the actual length of their products or the bearing surface. If they did, then you could check before you buy them.

Backup plans
Reloading software allows you to build up a load using different powders and bullets, and it also allows you to experiment with the cartridge’s overall length. It will calculate theoretical chamber pressures and muzzle velocities, and QuickLOAD has proven to be pretty accurate when comparing its data with the actual data obtained from a chronograph. If you drop a powder charge too low, the software will also flag up a warning if there is not going to be sufficient chamber pressure to overcome the neck tension and force the bullet into the rifling.
Bullet and powder manufacturers are also very helpful and will usually respond if you email them requesting data for a particular bullet. However, their response will always include a disclaimer, which is normal. They are constantly doing research with their products and often have test information that has not yet made it into published reloading data. Hornady has always responded relatively quickly to questions or queries and their technical experts really know their stuff.

Conclusion
Bullets with similar characteristics can be loaded using the same data, but with caution. You must begin with the published starting load, watch for pressure signs, and check the muzzle velocity. Working up the powder charge in small increments while continuing to watch for pressure signs or difficult extraction, you should be able to find a load that works well with your new bullet.
Even those of us who do not like technology have found that reloading software is very useful, and it also flags up warnings of potential pressure issues before you have done any actual reloading. This saves time and avoids firing potentially risky loads.

Contact: JMS Sporting – QuickLOAD – www. quickload.co.uk