Fibre cartridge wads
Besides checking our cartridges are loaded with the correct wad type to comply with the rules of the ground we are shooting on, it’s likely we don’t give much thought to that small item between powder charge and shot load. Prior to the introduction of plastic, all wads made from ‘traditional’ materials such as felt, fibre and cork and these are increasingly required again today, with grounds insisting on their use for environmental reasons. The one-piece plastic cup wad remains the top choice for major competition use but moves against plastics have increased such that, in the UK at least, cartridge sales have swung back in favour of fibre wad cartridges. The same also applies in the game shooting spheres, as farmers and landowners move away from plastic wad litter on their ground.
When plastic wads were first introduced, shooters were regaled with their many advantages; some promotional material made claims for what would now appear to be rather optimistic performance improvements against traditional wads.
Such claims may, in part, explain why some shooters feel disadvantaged when required to use fibre wad cartridges. Need they feel concerned, and, if so, how much difference does it make?
Key wad functions
All main driving wads, of any type, must fulfil certain key functions with the prime one being to provide an effective seal between the rapidly expanding gases produced by the propellant powder upon ignition and the shot charge.
This gas seal, known as obturation, provides the thrust that transfers the gas energy to accelerate the shot charge to velocity to perform the task required.
Richard Atkins looks at the wad, a small but vital cartridge component, and analyses its role and the material facts
Effective obturation is important for two important reasons: making efficient use of the gas energy, and preventing hot gases getting past the wad, where it can cause issues. Key potential issues are disruption of the pellets resulting in irregular patterns and, more seriously, shot balling.
Traditional wads are basically a tightly fitting ‘bung’, which seals the bore and separates the powder charge from the shot load. They are fundamentally the same as the wadding used since early musket and muzzle loading times, where a simple punch was used to cut wads from a variety of available materials.
Experience showed that felt materials were particularly useful for making wads, being strong enough to stay intact while sufficiently flexible to expand and form a seal. The best performing among all felt materials so far discovered is that made from wool and white wool wads retain the reputation for being the best traditional
“Traditional wads are basically the same used since early musket and muzzle loading times”
cartridge wad material. Only the advent of plastic wads has reliably surpassed the performance of wool felt.
Fibre wads
To date, the most successful and cost effective material to replace white wool felt is vegetable fibre, as initially used as an industrial insulation material. Fibre wads were cut from fibre boards on special machines capable of producing many wads simultaneously. Actual fibres used vary, some being by-products, such as wood pulp and sugar canes, otherwise waste material from other industries. One successful example of vegetable fibre wads are the Eley Kleena wads introduced in 1959. These were made available to home loaders back in the day (I still have some early examples). Current Kleena wads (now called Kleena Evo 5) use a paper-based material and are lighter in colour than the originals.
The name Kleena derives from their claimed ability for reducing bore fouling. Kleena wads are lubricated with a soft wax in a ‘ring-waxing’ process and are usually used in pairs, with two shorter wads being used to make the required wad column length, in conjunction with an over-powder sturdy card disc called a ‘nitro’ card. The nitro card aids gas sealing and, importantly, prevents lubrication from the fibre wad from leaching into the powder and causing a misfire. All conventional fibre wad cartridges use either an over powder card or plastic obturator disc under the wad.
A high percentage of the world’s major cartridge manufacturers currently use fibre wads from Diana, the Italian maker, which produces a huge range in different calibres and lengths. These are readily identified by being long enough to use a single wad instead of two (which simplifies the loading process and may be cheaper) and by their dark colour plus a thin plastic film at each end. This film helps prevent small shot pellets from becoming embedded into the surface of the wad under acceleration set back forces.
Fibre wad manufacture is fairly straightforward but to make consistent, high quality fibre wads is demanding. Particularly important is maintaining precise wad diameter to avoid ovality and also the tendency to cut them tapered.