Rifle bedding is a process of providing a rigid and consistent foundation for a

rifle A rifle is a long-barreled firearm designed for accurate shooting, with a barrel that has a helical pattern of grooves ( rifling) cut into the bore wall. In keeping with their focus on accuracy, rifles are typically designed to be held with ...

’s operational components, by creating a stable and close-fitting bearing surface between the gun’s functional parts (i.e. the receiver housing the

barrel A barrel or cask is a hollow cylindrical container with a bulging center, longer than it is wide. They are traditionally made of wooden staves and bound by wooden or metal hoops. The word vat is often used for large containers for liquids, ...

led action) and its support part (i.e. the

stock In finance, stock (also capital stock) consists of all the shares by which ownership of a corporation or company is divided.Longman Business English Dictionary: "stock - ''especially AmE'' one of the shares into which ownership of a compan ...

) that do not deform with pressure or shift under the

shear stress Shear stress, often denoted by ( Greek: tau), is the component of stress coplanar with a material cross section. It arises from the shear force, the component of force vector parallel to the material cross section. '' Normal stress'', on ...

of the

recoil Recoil (often called knockback, kickback or simply kick) is the rearward thrust generated when a gun is being discharged. In technical terms, the recoil is a result of conservation of momentum, as according to Newton's third law the force r ...

from firing. This is for the goal of

accurizing Accurizing is the process of improving the accuracy and precision of a gun (firearm or airgun). For firearms, accuracy is the ability to hit exactly what one is aiming at, and precision is the ability to hit the same place over and over again in ...

the rifle and (to a lesser extent) prolonging the life of the stock. The bedding process is often an aftermarket improvement.

Purpose

Increasing accuracy

Bedding increases accuracy in part by relieving stress on the action. The rifle's action will rarely sit flush in the stock without bedding. This causes the action to flex when tightening the bolts holding the action to the stock. This flexing results in inconsistency during operation, which accumulates to a loss of accuracy over time. Bedding will create a flush surface for the action and prevent flexing. Bedding also reduces movement of the action in the stock. Without bedding, the action may be more likely to shift after a shot. If the action shifts and does not return to same spot in the stock the rifle will lose the ability to maintain zero.

Prolonging stock life

Bedding can help prolong the life of the stock. Repeated recoil forces can cause movement of the action in the stock. As the action moves, friction can create wear in the stock surface. Eventually the repeated wear can ruin the stock.

Methods

Bedding involves molding an

epoxy Epoxy is the family of basic components or cured end products of epoxy resins. Epoxy resins, also known as polyepoxides, are a class of reactive prepolymers and polymers which contain epoxide groups. The epoxide functional group is also co ...

-based material onto the stock recess to fill away the gaps within its contact surface with the receiver (known as glass bedding), and/or inserting a metal cylinders (which act as

compression member Compression members are structural elements that are pushed together or carry a load; more technically, they are subjected only to axial compressive forces. That is, the loads are applied on the longitudinal axis through the centroid of the memb ...

s) around the action screws to reduce compressive shifting (known as pillar bedding). The receiver and the stock are sometimes fastened indirectly through an intermediate piece (usually made of rigid materials such as

aluminium alloy An aluminium alloy (or aluminum alloy; see spelling differences) is an alloy in which aluminium (Al) is the predominant metal. The typical alloying elements are copper, magnesium, manganese, silicon, tin, nickel and zinc. There are two pr ...

) known as a bedding block, which multifunctionally serves as a larger pillar, a bedding surface and even recoil lugs. The contact interface on the stock may also be substituted by a metallic bedding frame known as a

chassis A chassis (, ; plural ''chassis'' from French châssis ) is the load-bearing framework of an artificial object, which structurally supports the object in its construction and function. An example of a chassis is a vehicle frame, the underpar ...

, which is either embedded within the stock, or even completely replacing the stock like the lower receiver on many modern modular

semi-automatic rifle A semi-automatic rifle is an autoloading rifle that fires a single cartridge with each pull of the trigger, and uses part of the fired cartridge's energy to eject the case and load another cartridge into the chamber. For comparison, a bolt ...

s. Skim bedding refers to an adjustment of a glass bedding job, usually after wear and tear from use, which consists of removing a small layer of the bedding material — usually up to around — and adding new bedding material on top of that. Several different bedding methods can be used depending on the type of stock, desired results and level of experience of the person attempting to perform the bedding. Methods include: * Full contact bedding of the action with the barrel floated. * Full contact bedding of the action and the barrel. * Full contact bedding of the action with a pressure-bearing pad for the barrel. * Pillar bedding of the action with the barrel floated. * Full length aluminum action bedding block. Full contact bedding of the action with the barrel floated is a very common method for long range rifles with a heavy barrel. A free-floating barrel will generally produce the greatest accuracy. However, a pressure pad under the barrel just forward of the action can sometimes improve accuracy by acting on barrel harmonics and reducing stress on the action from the weight of the barrel. Pillar bedding can be used to float the action as well as the barrel, but the process is more difficult.

Precautions

If performed improperly, bedding can destroy a rifle. Mechanical locking occurs when bedding material is allowed to harden in holes or around protrusions on the action. If locking occurs, the action can be permanently fixed to the stock. Extreme measures may have to be taken to separate the stock from the action, possibly destroying one or both. Improperly applied or insufficient release agent can cause the bedding material to bind to the metal. If the trigger assembly is not removed prior to bedding, epoxy can seep into the trigger assembly and ruin it.

Purpose

Increasing accuracy

Prolonging stock life

Methods

Precautions

References

Further reading