Rifle bedding
Rifle bedding is a gunsmithing process of providing a rigid and consistent foundation for a rifle’s operational components, by creating a stable and close-fitting bearing surface between the gun's functional parts and its structural support that do not deform with heat, pressure and moisture, prevent noisy/loosly fitting components or shift under the shear stress of the recoil from firing. The bedding process is often an aftermarket modification, and is done for the goal of accurizing the rifle and prolonging the service life of the stock.
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 fixing screws that hold the action to the stock. If the stock is wooden, it will also expand or shrink significantly with environmental changes such as temperature and moisture, which causes changes in action screw tension. These result in inconsistencies during operation, which degrades accuracy. Bedding will create a flush bearing surface for the action and prevent flexing.Bedding also reduces minute movements of the action within the stock. Without bedding, the action may be more likely to shift after each shot. If the action shifts and does not return to same spot in the stock the rifle will lose the ability to maintain zero.
The presence of the bedding material also adds a small amount of extra height to the action, and creates more of a gap between the barrel and the fore-end of the stock, allowing the barrel to be better floated, which helps improve accuracy.
Prolonging stock life
Bedding can help prolong the life of the stock. Repeated shearing forces from recoils can create focal wear and chips in the stock surface, and eventually ruining the stock with repeated usage. Bedding redistributes stress over a larger area, reduces shifting between the action and the stock, and creates a hardier, protective epoxy coating over the softer stock contact surface, thus protecting it from mechanical wears over time.Methods
Bedding involves molding an epoxy-based material onto the stock recess to fill away the gaps within its contact surface with the receiver, and/or inserting a metal cylinders around the action screws to reduce compressive shifting. The receiver and the stock are sometimes fastened indirectly through an intermediate piece 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, which is either embedded within the stock, or even completely replacing the stock like the lower receiver on many modern modular semi-automatic rifles.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.