Precision rifle stocks versus chassis systems One of the bigger choices you’ll make outfitting your precision rifle is deciding whether to equip it with a traditional stock or a chassis system. Both have advantages, but which is a better option for you?
What do they do? Stocks and chassis systems serve as a physical interface between the shooter and the rifle. While the optic allows the shooter to see his target and the trigger is the mechanism for initiating the shot, the stock or chassis allows the shooter to maintain a proper body position and head alignment with the optic. Mechanically, the stock or chassis holds the feeding mechanism (for a repeating rifle), houses the trigger, and allows for the attachment of accessories like bipods and night vision optics. Stocks and chassis serve an important role in rifle accuracy- if the rifle’s action isn’t properly mounted into either, in a stress free installation, the rifle will not shoot to it’s full potential. The methods used to provide a stress free installation on stocks and chassis differ and we will discus why below.
Stocks and Chassis Systems- same thing, only different Stocks- For precision rifles, quality stocks are typically made out of fiberglass, Kevlar or carbon fiber. You’ll still see wood in hunting rifles, however, it is an anomaly in precision rifle world. While you may encounter an injection-molded stock on a factory rifle, they are normally discarded in favor of more durable and less flexible options. Normally a stock is one piece. Sometimes they will be equipped with bedding pillars, often made of aluminum. Historically, the pillars were used in wood stocked rifles to prevent the movement of the stock from effecting accuracy. Since wood has fallen out of favor with the precision rifle crowd, now, the biggest function of the pillars is to provide proper spacing between the bottom metal and the action, ensuring rounds feed well from the magazine to chamber.
Most stocks are bedded to allow the action a stress free installation. The bedding process requires a fair amount of skill, and while it isn’t beyond the reach of a serious do-it-yourselfer, it is a fairly skilled process. After the bedding is completed, the bedding compound needs to be protected from solvents to prevent damage. Stocks require bottom metal to house the trigger guard and magazine feeding systems. While many factory rifles like the Remington 700 are readily available with a floor plate magazine system, most precision rifle shooters choose to upgrade to a detachable magazine typically using a detachable magazine based on the Accuracy International AICS design. Most of these systems require the stock inletting and installation. The Magazine systems can range in price from just over $100, to nearly $400.
Chassis systems avoid the need for bedding in their design. Typically, the chassis systems are designed with geometry that supports the action in such a way that simply screwing the barreled action into the chassis provides a stress free installation. No bedding compounds, release agent, or anxiety as the compound cure hoping you can remove the barreled action from the stock. Since the detachable magazine system is built into most chassis the alignment of the magazine to the action is normally correct. The separate spacers (pillars) do not need to be installed, and the shooter doesn’t need to be concerned with parts from different manufactures aligning. Additionally, incorporating the bottom metal into the chassis system will typically save money. When pricing chassis and stock systems of similar quality, the completed systems, including the bottom metal, stock inletting, night vision mounts, and bedding costs will often favor the chassis as a better value.
Installation of a chassis is a breeze. Some simply require the rifle to be removed from the stock and screwed into the new chassis. More complex systems, like the MDT TAC-21, require removal and reinstallation of the trigger. The instructions included with systems like this include directions on how to accomplish this themselves.
Chassis will typically offer more versatility than a fiberglass stock. Some allow the shooter to use AR-15/M16 M4 compatible stocks and pistol grips, allowing the stock to be upgraded from legacy systems as new attachments become available. More importantly, the ability of the individual user to fit the chassis to his particular shooting style or build, will reap huge benefits downrange with increased performance.
Chassis tend to work better in switch barrel applications as well, since the generous barrel channels typically allow the barrel to be unscrewed without removing the barreled action from the chassis. Some systems go further and include a continuous mounting rail along the top of the chassis system. For instance on the TAC-21, the top rail is a continuous 20 MOA rail, providing necessary cant to optics for long range shooting and allowing any from mounted night vision optics, like the AN/PVS-22 or AN/PVS-27 to be mounted with the same cant as the optic. This is a huge advantage in low light applications.
Which one is more accurate? As far as accuracy is concerned, my experience is that a given barreled action in a quality well bedded stock will normally have a slight advantage to a chassis system. This sin’t saying chassis don’t shoot, they do, and we’ve had some chassis, like the TAC21 that shot exceptionally well. When compared to a low quality injection molded factory stock, both will offer an increase in downrange performance.
What does Rifleshooter.com prefer? If money isn’t an issue and you want a stock I prefer the McMillan A5 with Badger M5 bottom metal (Surgeon bottom metal is also nice). For a chassis, the Accuracy International AICS AX 2.0 chassis is exceptional and is priced accordingly, however, keep in mind it uses a slightly different magazine than he traditional AICS mag. If you want a chassis that costs less but works just as well, the entire line of Modular Driven Technologies systems deserve serious consideration. Rifleshooter.com wrote the first reviews of the TAC21, HS3 and LSS and they work as advertised and are a great value for the money. For a budget stock, an H-S Precision or Bell and Carlson stock will work provided it is bedded properly.