Crossbow Tech Tip - Molded Rail vs. Machined Rail vs. Carbon Fiber Rail

Friday, June 2, 2017

There are several different types of materials used in manufacturing crossbow rails, each offering different benefits. The 3 most common materials are composite, machined aluminum and carbon.

Composite rails are going to be the least expensive. They are generally going to be fairly lightweight but molded with lower tolerances. This typically results in loss of accuracy and durability. When using a mold it is very difficult to duplicate each part to exact specifications. We have experienced several different instances on a variety of makes and models using molded materials where the fit might be slightly off. This will require some force to put the bow together. Cable slides may also be too tight to allow for free movement, which will directly affect the performance of the crossbow.

Next is the machined aluminum rail. This type is usually higher in price than crossbows with composite rails but generally cheaper than the carbon fiber. This can vary based on other components and construction of the bow. The machined aluminum rail is much stronger than the composite rail and has tighter tolerances giving you much better accuracy. With the tight tolerances that the machined aluminum rails offer you will generally have a very precise fit resulting in all the parts working as designed.

Carbon is basically the best of both worlds. Carbon rails are lightweight while offering high strength and durability. In some cases they may not be the most accurate depending on the materials and process used. With the growth in carbon fiber technology manufactures are continuously finding cheaper ways to construct carbon parts. Some of these low grade parts are closer to the results of a composite rail with lower tolerances resulting negatively in a loss of accuracy while lowering the price of the bow. In most cases the price can tell you a lot about the quality and construction of the carbon fiber used (but this is not always the case).

The most overlooked aspect of the accuracy in the rail design is the fact that most arrows ride directly on the rail. If the rail is not perfectly straight the arrow can be pushed to one side or the other, which your scope can compensate for. This will make your bow appear accurate at closer ranges like 20 or 30 yards but ultimately when you push it out to longer distances or with addition of broadheads, the bow will shoot as if it were out of tune.

A few examples of crossbows with these various rails would include a PSE Fang LT with a molded rail, an Excalibur Micro Raid with a machined aluminum rail, and a TenPoint Carbon Phantom with a carbon rail.  If you have any questions about a crossbow you're considering, feel free to contact us by email or give us a call at 715-386-4188.