A Comparison of Gunstock Materials
Wood is the traditional material and of course nothing looks better to most people than a fine piece of quality gun stock wood. The thing that makes wood beautiful is also what creates the problems with wood, it was once a living thing. Wood expands and contracts with changes in moisture content and temperature which can cause significant accuracy problems at the worst times. Laminating a stock from various thin plys of wood may help to alleviate some of these stability problems as does pillar bedding and actually removing all the wood that would affect the bedding due to changes in moisture. When a wood stocked rifle shoots well it is as good as any, but will it shoot well tomorrow or after spending a day in the rain? After many years of inspecting broken and deformed laminated stocks we have decided that a quality gun stock of one piece of wood is better than one from laminated materials.
Synthetic stocks are generally stocks that are injection molded and are available at low cost. These plastics are often reinforced with short fibers which can be injected into a mold through the plumbing required by the process. Long, carefully aligned, fibers are not present and plastic resins used are of a type dictated by the manufacturing process rather than by the end use. color is consistent throughout and if sectioned would reveal a homogeneous material. Synthetic stocks are excellent value for utility and casual use where accuracy is not important.
Fiberglass has become a generic term to generally mean fibre reinforced plastics. The great strength of these materials comes from the reinforcing fabrics being combined with plastic resins. The longer and more carefully aligned these reinforcing materials are, the greater the ultimate strength will be. These reinforcing materials can be glass, kevlar and carbon fibre, among others. Stability is achieved with materials that are dense enough to resist compressive and shock loads and are dimensionally stable with changes in temperature and humidity. Color is best close to the outer surface through the use of a gel coat layer, although if painting is intended color is not important. A sectional profile would reveal different layers of materials. Ideal for consistent accuracy and resistance to the elements.
As you can see, there can be a lot of confusion with the terms fiberglass and synthetic. Be sure you understand how the stock you intend to buy was actually manufactured and with what materials.
How we do it
We have been building fibreglass gun stocks for over thirty years and our customers have acquired a long list of international trophies. Our stocks are built with one ultimate goal in mind, stability and accuracy. Our stocks are built by hand to achieve the best combination of strength and stability.
They are built with epoxies formulated to give the best structural characteristics in composition with a variety of reinforcing materials and in fact the next time you are in an airplane you may be flying with the same epoxy you shoot with, our epoxies are certified for aircraft construction. A close watch on the resin to reinforcing materials ratio is required to achieve the best strength to weight performance and all our stocks are post cured at elevated temperatures to maintain their excellent properties through a wide temperature range. The action area in our standard fill is composed of a solid composition to give a solid and stable base to the bedding. The forend is filled with a light weight material which provides excellent stiffness without adding non-structural weight. Butts are solid filled in target styles to allow the installation of cheek piece adjusters and may be foam filled to save weight on other models. Foam has its place in a precision stock, if careful thought is given to it's use. All of our stocks use carbon fibre in critical areas to add stiffness at low weight.
We have CAD, CNC and digitizing facilities. All our inlets are done CNC and many of our stocks have been produced with the aid of this technology. As an example the Stiller "F" model was produced completely with this technology and has many details which are very hard to see in the photographs. It is styled after the Stealth fighter and even has intake ports on the forend which can be used as barrel cooling slots. Cool. What is very noticeable on Robertson stocks is the detail, straight lines, sharp corners and attention to symmetry.