I always enjoy hearing from our customers who have purchased our stocks. A few months ago, a hunter contacted us by e-mail and wanted his stock repainted, he said he got it a long time ago and hunted with it every year. As it turned out, he had got one of the first 100 kevlar – graphite stocks we ever made, and we really wanted to see it and how it held up.
When we received the stock, we were pretty surprised. He had included the original invoice; he purchased the stock 18 years ago. Except for a couple of dings and a pretty beat up Pachmayr pad it looked great. We had bedded an old tang safety Ruger 77 in the stock, and the bedding still looked perfect.
As it turned out, our hunter was just sick of the original camo color and wanted it painted black, he said he had sighted it in when he got it, checked it every year and it never moved.
So why had this stock provided so many years of service? To fully understand why, let’s first look at stock manufacturing technology.
If a shooter decides to purchase a composite rifle stock, his choices are: injected molded, hand laminated, or a hybrid combining the two technologies.
The injected molded stocks are sold on most factory rifles available from Winchester, Ruger, Remington, Browning and others. These stocks are inexpensive to manufacture (usually $7-10) and can be called composite. The injection molding process is to inject hot plastic (some with glass fibers) into a mold and allow it to cool – instant stock. If you are looking for performance, they don’t work. The material used is heavy – as heavy as walnut, they flex way too much to provide any accuracy – try bend and flexing one, and they have no stability – on a hot day, they will warp. Plus, they cannot be bedded, ever wonder why some companies use hot meld glue to bed the barrel actions? Epoxy bedding compound just won’t stick to the material. And, they break, snap like twigs! The material is very porous and fills with salt, oil, contaminates and causes deterioration. Given a choice between a wood stock or molded, I would choose the wood.
The hand-laminated stocks can be split into 2 groups: epoxy/glass and polyester/glass. Both materials are liquid resins that require a catalyst for cure and are reinforced with fiberglass, Kevlar, or carbon fiber cloth for strength. The resin and cloth are wet out and put in a mold cavity to make the desired part. This technology makes a firm, rigid, durable structure and is used to make boats, racing car bodies, airplane parts – the list can be endless.
Epoxy resin has a 3 dimensional molecular structure, high resistance to impact damage, complete 100% cure cycle, complete stability once cured, unlimited life, and is light weight. Polyester resin is less expensive, has a 2 dimensional molecular structure, is brittle, with an incomplete cure cycle (usually 70%) up to 7 years and then starts to deteriorate, unstable in heat and cold and is heavier. Each material has its place in composite manufacturing, for rifle stocks, look for an epoxy product.
The hand laminated stocks are the most expensive to make. It is a labor-intensive process. Lamination time on a complex stock design can take 4 or more hours. The strength and stability of the stock depends on the blending of the cloth and resin at the optimum 70% cloth – 30% resin and reinforcing the critical stress areas to eliminate and future problems. The stocks are made using fiberglass cloth, Kevlar – for lightweight, or graphite – for stability and rebound. Then each stock is hand finished and painted.
Bedding is mandatory with a glass stock, I have seen groups cut in half with a good bedding job. I would not consider one without bedding – professional bedding!
When made right, these stocks are lightweight, strong, stable, trouble free, and an extremely durable product. Several companies offer good hand-laminated rifle stocks, they are the standard by which all stocks are judged.
Hybrid stocks are usually some combination of technologies designed to cut cost by eliminating the ‘hands on’ part of the process. These stocks offer a lower price but have to compromise weight and longevity. They are usually reinforced with aluminum for strength. Since aluminum has different physical and mechanical characteristics than composites, needless problems are created. It is impossible to get aluminum and composite resins to bond indefinitely; you can only create a physical bond because the materials are so dissimilar. Target shooters have used aluminum stocks and they require constant resighting from changes in weather conditions since aluminum is greatly affected by heat. However, gunsmiths seem to like these stocks because they are advertised as not needing bedding. I guess I would prefer not adding the 3rd material in the mix between steel and glass, keep it simple.
Ok, now back to our hunter with his 18 year old stock and why it never failed him. The technology used in making his stock was not too far away from what we do today, there have been refinements in the resins, hardeners and the cloth, and now, we make each stock specifically to a customers restocking job. Some of the newer cloth blends allow us to make lighter and lighter stocks; I would have never imagined a 12 OZ hunting stock.
His stock was kevlar/graphite epoxy hand laminated using monocoque construction – meaning there is a continuous cloth lamination throughout both the exterior and interior (receiver and barrel channel). The interior of the stock thru the receiver was a solid epoxy milled fiber matrix, with the forend and butt filled with polyurethane foam to dampen noise and vibration. Using this type of construction the stock absorbs the load put on it during the recoil of the weapon and instantly rebounds to be ready for the next shot.
The rifle was bedded with the same epoxy that was used in the construction of the stock so it has both a chemical and mechanical bond to the stock and the same physical characteristics as the stock. This is very important since the bedding ties the stock, barrel, and receiver together making it work as a single unit; the receiver and floorplate was bedded 100%, the cartridge length of the barrel bedded and ‘floated’ from there out. The rifle was bedded without any pillars although if I were doing the rifle today, I would use pillars. The stock made and fitted this way has given years of service and should continue to do so for many more years to come.
I like to think there have been a lot of changes in technology since we made this stock in 1985 and there have been a few, but most of the changes are with the rifle owners. I seldom hear “I just like the looks of wood” or “I’ll quit hunting before I use one of those damn plastic things”. For accurate hunting and target rifles, glass is the 1st choice; the modern day hunter demands it. A well made, and well-finished glass stock mounted on a custom barreled receiver performs beyond anyone’s expectation – today and in 18 years.