Shoot’n, Fish’n ‘n’ Hunt’n

When comparing cartridges, we put way too much emphasis on the cartridge case and nowhere near enough on the projectile.

Cartridge Case or Projectile?

Part 2 – How to Sort out the Mess!

In Part 1, I discussed how the comparison of one cartridge case versus another, without listing important specifications such as load data, projectile parameters and barrel dimensions, is quite pointless and inconclusive. In this part I am going to make some suggestions about how the gun industry might correct these shortcomings and finally provide real and meaningful information for the firearms user.

Did you miss Part 1?  If so, you can go to Part 1 by clicking here: 

Part 1 – Which is the Most Important?

So, considering the discussion in Part 1, this left me wondering whether our virtual ‘hero-worship’ of cartridges is misplaced. While we need to be able to specify the cartridge case that a particular firearm is chambered for, simply specifying the cartridge name is insufficient information to work with. A cartridge can be loaded with a wide range of projectiles, some of which might be totally unsuited to the twist rate of the barrel or for the velocities produced by that load. To be able to compare cartridges, effectively and realistically, we really need reference to the cartridge, the projectile, the twist rate of the barrel and the velocity range that the projectile will work within. Obviously, there are too many parameters to be able to include all of this information in the cartridge name. To try and do so, would be very complicated and extremely clumsy. However, without reference to all of these variables it is not possible to truthfully compare different cartridges and calibres.

Projectile Design Parameters

Fortunately, some bullet makers now list the range of velocities that their projectiles are designed to work in – and this is a good first step. However, many other bullet makers still fail to provide this information. I often wonder if that is because they simply don’t know the velocities or because they know that the answer would be detrimental to sales. When we buy any projectile, without knowing the velocity band of that design, we are simply taking pot-luck.

So, in some cases, we might know the design parameters of the projectile. We have also read all of the ‘advertorials’ about how great a particular cartridge is. So we are part of the way to being able to make viable cartridge comparisons. However, there is still a lot of other vital information that we are not provided with when we compare cartridges and when we buy a new firearm.

Barrel Twist Rate

Barrel twist rate is one of the least understood, and most frequently ignored, parameters that we need to consider when comparing cartridges and when buying firearms. If the twist rate of your barrel does not match the projectiles you wish to use, then you will never get good results. With a mismatch between twist and projectile, accuracy will range between poor, in the least worst cases, through to abysmal in extreme cases.

When we buy a new firearm, it is not always clear what the twist rate of that firearm is. Some manufacturers, such as Ruger, specify the twist rate and make this information readily available in brochures and on their website. However, other manufacturers do not specify the twist rate and, with some, it is almost impossible to find this information. In addition, the manufacturers sometimes change the twist rate of their barrels mid-production. The website and the brochures might tell you the twist rate is one thing but you still might find that your rifle has a different twist rate.

You cannot simply assume that a firearms manufacturer, or a gunsmith, has fitted the correct twist barrel for your selected cartridge and to do so is fraught with danger. There have been many examples, over the years, where major firearms manufacturers have fitted their products with barrels with inappropriate twist rates. This can happen when the manufacturer has failed to keep up with projectile developments or failed to foresee future developments. It has also happened when they misidentified the purposes that their customers will use that firearm for.

In addition, it is not uncommon for gunsmiths to fit barrels to customer’s rifles with only scant, or no, regard for the twist rate of the barrel. Perhaps opting for the cheapest barrel rather than selecting the correct one. Alternatively, some customers have fixed ideas about the barrels they want fitted even though they may not fully understand the importance of barrel twist rates. Try and determine the twist rate of a re-barrelled firearm, that you are thinking of buying and you might have troubles finding that information.

The only choice that owners of factory firearms, whose manufacturers do not readily provide twist rate data, or for re-barrelled firearms, is to measure the twist rate themselves. However, it might be a little late for that if you find that the firearm you just spent a pile of money on is fitted with a barrel  which has a twist rate that does not suit your intended purpose for that firearm.

Barrel Dimensions

Another complication, to the whole cartridge comparison issue, is that the actual groove and bore dimensions can vary quite a bit between barrel makers. This is especially so for cartridges that have been around for a long time, as industry standards were not so rigid in the past. A particularly notable example of this would be the .44/40 cartridge that has a nominal bore size of .427”. Yet, older guns can vary anywhere up to .432” and modern guns are often made using .44 Magnum barrels which are .429”. If you look at the .450/400 cartridge, the bore size is a nominal .411” but original guns can vary between .410 and .414” and most modern .450/400s are .410”.

When you compare European cartridges, that have been accepted in the USA, you find variations, too. The Europeans make their 7mms with a diameter of .285” and their 6.5mms are .265”. American gun makers use .284 and .264 respectively. These small differences can usually be ignored but sometimes projectiles are not at the nominal diameter either, and the end result can be a compound of errors with a resultant accuracy that is less than desired. Unless you know, and understand, all of these dimensional variations, you can find cartridge comparisons and load selection extremely difficult.

So how do we fix all of this mess?

In the past, the British marked their firearms with a lot more information that we do today. Not only did they stamp the cartridge identifier on the barrel, but also the regulated load, including projectile weight and pressures. Today, all we get is the cartridge name. However, I believe that it is time to rethink this approach and to expand on the practices of the old British gun trade. Today, we cannot just stamp bullet weight and pressures, as they did, because the modern practice of reloading has provided far too many component choices for that simple approach to work. Yet there is a solution that would make things a lot easier for shooters, and especially reloaders. It would also keep the gun and ammunition makers honest. The solution is if the barrels of all firearms were stamped with the cartridge name, the bore and groove dimensions and the twist rate.

Complete and Accurate Ballistic Data

With firearms more clearly marked, with all of the necessary and relevant information, then we just need to sort out the lack of information on ammunition and projectiles. Simply saying that a particular cartridge is loaded with a 150 grain Pointed Soft Point bullet, for example, and that it has a claimed velocity of 2,500ft/sec, is no where near enough information. Ammunition and projectiles should also specify the velocity range that that projectile is designed for, the twist rates that it works in and any velocity information, which is published by the manufacturers, should be realistic and should include the ambient conditions of when those velocities were measured. At the very least, it should include ambient temperature.

Of course, the publication of this information would require the ammunition manufacturers to think more carefully about the design parameters of their products. It would also require them to coordinate the performance parameters, of their ammunition, more closely with the design specifications of the firearms products from the firearm manufacturers.

With this information on both the firearm and the ammunition, shooters could then select the factory ammunition that is loaded with the correct projectiles for their purpose. Buying factory ammo, without knowing projectile design parameters, actual dimensions and intended twist rate, is really just a lucky dip. For reloaders, knowing this information, while also understanding the important relationship between projectiles and twist rate, would allow them to accurately tailor their loads to their rifles. Further, they could do this with a lot less of the blind experimentation that has been a key characteristic of load development till now.

When we finally have firearms that are clearly marked with cartridge, bore dimensions and twist rate. When we finally have projectiles and factory ammunition that is marked with the design parameters for the projectiles in use, i.e. velocity range and ideal twist rate, and when that factory ammo is marked with actual velocities, and the ambient conditions that it was measured at, then we might finally be able to select the correct ammunition for our firearms. In addition, and in response to the question that prompted this discussion, we would finally be able to compare one cartridge against another and come up with an idea of which is truly the superior round. Till that time comes, most of what you read about cartridge superiority is just pure speculation!

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