The Epic Battle Between Carbon Fiber and Fiberglass: Which is Best for Your Rifle Stock?

In the world of composite rifle stocks, there's a showdown between two contenders: carbon fiber and fiberglass.

Before we dive into their differences, let’s cover what these two materials have in common.  Both are extremely durable and paintable.  Both are drastically more rigid than the plastic stocks that many factory rifles ship with today.  Rigid components lead to accuracy.  Unlike wood, carbon and fiberglass are both non-porous, which means they can’t swell or shrink in response to temperature and humidity changes, like wood does.  This means better shot-to-shot repeatability.

The processes of building a rifle stock out of carbon fiber and fiberglass are extremely similar.  While it requires a little more labor to finish a carbon fiber stock, the assembly is nearly identical.  When properly designed, engineered and constructed, both materials yield a stock of phenomenal quality. 

What are the differences?  Let’s look at the base materials. 

Carbon Fiber

Carbon fiber made its debut in the aerospace industry.  Today, it’s used in everything from fighter jets and racecars to drones and knife handles (not to mention rifle stocks).  Carbon fiber is much stronger than steel in terms of strength to weight ratio; it’s roughly five times stronger than steel for its weight. It’s made of crystalline carbon filaments 100 times smaller than human hair, forming a tight, chain-like bond.

These fibers are woven into a fabric-like sheet, which is impregnated with an epoxy resin to form its composite structure.  Once cured, carbon fiber provides excellent stiffness and corrosion resistance.  It also exhibits extremely low thermal expansion characteristics, so changes in temperature have near-zero effect on the material.

The only downside to carbon fiber is its cost.  You pay for performance.

Fiberglass

Fiberglass was invented in the 1930s and was first used as an insulator.  It offers versatility in terms of strength and flexibility, making it suitable for a wide range of applications, including construction, marine, automotive, etc.  It doesn’t corrode and it’s extremely impact-resistant.  In other words, it’s as tough as nails.  It’s been used in manufacturing rifle stocks for much longer than carbon fiber has. 

When compared to carbon fiber, fiberglass is relatively inexpensive, but it does weigh more.  Fiberglass stocks also tend to dampen vibration slightly more than carbon fiber. 

So, which is better for a rifle stock?

There’s a military mantra that applies here: “Mission drives the gear.”  In other words, there should only be two things that really weigh into your purchase decision.  A) What do you want to do with your rifle? B) Do you want to spend the extra money to save weight?

Let’s break that down.

Weight

How important is the weight of your rifle?  If you plan to hunt sheep or backcountry elk, the extra money may very well be worth the weight savings.  On a big mountain hunt, an ounce in the morning weighs a pound in the evening, or so it seems.  There are backpack hunters out there who cut the tags out of their clothing and snap their toothbrush short in order to shave an ounce. 

Only you can decide how light you want your rifle to be, and where to save that weight.  You can save weight in the barrel, in the scope, in accessories, and in the stock.  Some shooters do all the above.  The stock is one of the best places to do it without compromising optical quality or barrel performance.

In rough numbers, a fiberglass stock can weigh up to 35 percent more than a carbon fiber stock.  For example, our Privateer stock weighs 31 to 32 ounces in fiberglass and 24 to 25 ounces when constructed of carbon fiber.

Of course, mountain hunters aren’t the only rifle shooters out there.  Some competitive shooters, from PRS to Benchrest, prefer a heavier rifle.  The heavier the rifle, the lower the felt recoil.  Heavier guns are more forgiving and generally easier to control during strings of fire.  A heavier stock also shifts the balance of the rifle toward the rear of the gun.  For these reasons, some people prefer fiberglass over carbon fiber.

Cost

In rough numbers, a fiberglass stock should cost about 40 percent less than a carbon fiber stock.  Some manufacturers charge nearly the same for the two, but the simple fact of the matter is that fiberglass raw material costs substantially less.  Further, fiberglass is easier to finish than carbon fiber.  At AG Composites, we feel that this savings should be passed along to the customer.

Aesthetics

Weight and cost should be the primary factors in your decision-making process, but there’s one more thing to consider.  Some gun enthusiasts really love the appearance of exposed carbon fiber on a rifle stock.  It does look very cool, especially when paired with a great camo pattern. 

The carbon fiber finishes AG Composites offers require a tremendous amount of labor and true craftmanship but, the results are second to none in the industry.  The finish on our fiberglass stocks is absolutely stunning as well.  However, due to the nature of fiberglass raw material, seeing the weave is not available.

A final word

We can’t speak for other stock manufacturers, but when you buy a fiberglass stock or carbon fiber stock from AG Composites, rest assured that the manufacturing processes are nearly identical.  As previously mentioned, there are extra steps during the finishing phase of a carbon fiber stock.

All our rifle stocks are made in the same facility in Alabama, with the same stock molds, the same production steps, the same quality control, and the same attention to detail.  All the various options – from models and sling mounts to paint colors and camo patterns – are the same across the board.

The cost difference between the two reflects the cost of raw materials and the amount of finish work required.  Carbon fiber stocks cost more than fiberglass stocks because the manufacturing inputs cost more.

Our suggestion is to let your weight tolerance and budget dictate which material to order.  Either way, you’ll end up with a rifle stock of exceedingly high quality.