Bedding Your Bolt-Action Stock – Pillar Bedding, Glass Bedding, and When Either One Actually Matters

Bedding is the most misunderstood accuracy modification in bolt-action gunsmithing. Shooters who have never done it treat it like magic. Shooters who have done it badly treat it like a disaster. Done correctly and for the right reasons, it is one of the most reliable accuracy improvements available on a rifle with a poor factory fit. Done when the rifle did not need it, it is an expensive way to create new problems. Here is the honest picture.

What Bedding Is and Why It Matters

Bedding describes how the action — the receiver, recoil lug, and tang — interfaces with the stock. When bedding is correct, the action sits in the stock with full, even contact at all critical surfaces: the receiver footprint, the recoil lug bearing face, and the tang area. When the action screws are tightened, the action is drawn into a precise, repeatable position that is identical every time the rifle is assembled.

That repeatability is what bedding buys. A rifle that returns to the exact same mechanical relationship between action and stock after every assembly and reassembly — after cleaning, after transport, after a hard season in the field — shoots from the same baseline on every range trip. The variables that affect accuracy are reduced by one: the action-to-stock relationship is not a variable anymore, it is a constant.

When bedding is poor — when the action rocks on high spots, contacts the stock inconsistently, or has voids where there should be contact — the action settles into a slightly different position under the torque of the action screws each time. Not dramatically different. Subtly different. Enough to shift point of impact between sessions, enough to produce unexplained variation that no amount of ammunition testing or scope work can eliminate, because the source of the variation is in the mechanical relationship beneath everything else.

Most factory rifles have acceptable bedding. Not perfect bedding. The production process uses inlet routing machines that produce consistent but not precision-fitted results. On inexpensive rifles the fit is rougher, on more expensive ones it is better, but almost every factory rifle benefits from improved bedding to some degree. Whether that improvement matters in practice depends on how accurate the rifle needs to be and how much of the available accuracy is being lost to bedding inconsistency.

Diagnosing Bedding Problems Before Doing Anything

Before spending time and money on bedding work, confirm that poor bedding is actually your problem. This is the same principle that runs through every article in this series: diagnose specifically before you treat generally.

The layout dye test described in the accuracy diagnosis article applies directly here. Apply a thin coat of machinist’s layout dye or lipstick to the bottom of the receiver — the full contact surface including the recoil lug face and the tang area. Reinstall the action in the stock with the action screws at correct torque. Remove the action and examine the stock inletting. The dye transfers where contact is occurring.

What you want to see: even, full contact across the entire receiver footprint and the full face of the recoil lug. What poor bedding looks like: isolated spots of high contact — a few patches of transfer with voids around them — indicating the action is rocking on those high spots. Or a recoil lug that shows contact only at its corners but not its face, indicating the lug is being forced into a pocket that does not match its dimensions.

A rifle with acceptable factory bedding — even if not perfect — and a bedding pattern that shows reasonably even contact across most of the receiver may not benefit enough from bedding work to justify the effort. A rifle that shows clearly uneven contact, a rocking action, or a recoil lug with poor face contact is a genuine bedding candidate.

The Two Methods — What Each One Actually Does

Pillar Bedding

Pillar bedding addresses a specific problem with stock material: it compresses. Whether wood or synthetic, the material around the action screw holes deforms over time under the repeated torque of the action screws. As the material compresses, the torque specification changes — screws that were correctly torqued when new produce less clamping force as the material under them settles. The action starts to move in the stock even with correctly torqued screws because there is less material resisting the movement.

Pillars are metal cylinders — typically aluminum — installed in the stock at the action screw locations. The action screws pass through the pillars and draw the action directly onto the pillar tops rather than onto the stock material. Metal does not compress under normal action screw torque. The clamping force is consistent from the first tightening to the thousandth, and the action torque specification remains valid indefinitely.

Pillar bedding does not create a full contact fit between the action and the stock — it only addresses the screw hole compression problem. If the action was rocking on high spots before pillar installation, it will rock on the same high spots after. Pillars are typically combined with glass bedding for this reason. But pillar bedding alone, even without glass, produces measurable improvements in rifles where stock compression was allowing action movement under torque.

Glass Bedding

Glass bedding — named for the fiberglass-reinforced bedding compounds originally used, though modern compounds use various filler materials — fills the voids between the action and the stock inletting with a dimensionally stable compound that cures to a precise fit around the specific action being bedded.

The process creates a custom-fitted bed for that specific action in that specific stock. The bedding compound flows into all the voids, contacts all the surfaces uniformly, and cures to produce a fit that is exactly matched to the action geometry. When the action is reinstalled, it sits in a surface that is shaped to its exact contour, with full contact across every intended contact surface, with no high spots and no voids.

Glass bedding addresses the fit problem. It does not address the compression problem — the bedding compound, while more stable than wood or synthetic stock material, can itself compress under extreme or repeated action screw torque over a long period. This is why glass bedding and pillar bedding are most effective when combined: pillars handle the compression problem, glass handles the fit problem.

Which One Does Your Rifle Need?

The honest answer is usually both, if the rifle needs bedding work at all. But the priority and sequence matter.

If the rifle has a synthetic stock in good condition with only mild bedding fit issues: Glass bedding the receiver area and recoil lug with a quality compound is often sufficient. Synthetic stocks compress less than wood under normal conditions, and if the screw hole areas show no visible crushing or deformation, pillar installation may not be the priority.

If the rifle has a wood stock, any age: Pillar bedding is the priority because wood compression is predictable — it will happen if it has not already. Pillars prevent the compression problem permanently. Glass bedding around the pillars addresses the fit.

If the rifle has a synthetic stock that has been heavily used with action screws torqued repeatedly over years: Inspect the screw hole areas for visible deformation or crushing of the synthetic material. If the material shows any visible compression, pillars are indicated along with glass bedding.

If the rifle shows significant action rocking — movement you can feel when you wiggle the action with the screws at correct torque: Glass bedding is the fix. The action cannot rock in a properly glassed bed that matches its geometry. Whether to add pillars depends on the stock material and history.

The Glass Bedding Process — A Realistic Assessment

Glass bedding is the most involved DIY gunsmithing job described in this series. It is not beyond a careful, patient home gunsmith, but it requires preparation, the right materials, and an honest assessment of the risk of getting it wrong. The downside of a poorly executed glass bedding job is an action that is bonded to the stock — literally glued in — which is difficult and potentially destructive to correct.

That risk is managed almost entirely by one thing: release agent. Before applying any bedding compound to the action, every surface of the action that you do not want permanently bonded to the stock must be coated with a release agent. Thoroughly. Including the action screw threads, the barrel near the receiver, the trigger guard, and every surface of the action that will contact the compound. Multiple coats of a quality release agent — paste wax, Johnson’s Paste Wax, or a dedicated mold release — applied and allowed to dry before the compound goes in.

I am going to say this plainly: if you rush the release agent step or apply it carelessly, you will spend the next several hours trying to separate your action from your stock with increasing force and decreasing success. The release agent is not optional and it is not a single wipe. It is multiple careful coats on every surface that could possibly contact the compound.

Materials needed

Bedding compound: Acraglas, Marine-Tex, Devcon Plastic Steel, or similar two-part epoxy bedding compound. Acraglas is the classic choice with a long track record. Marine-Tex is widely available and forgiving. All of these work. What matters is following the mixing instructions exactly — incorrect ratios produce compound that never fully cures.

Release agent: Johnson’s Paste Wax is the traditional choice and it works reliably. Apply at least three coats to the action, allowing each coat to dry before the next. Cover every surface that will contact the compound — not just the obvious ones.

Modeling clay: Used to dam off areas you do not want compound flowing into — the magazine well, the trigger cutout, around the barrel. Clay is easier to control than tape in this application.

Mixing supplies: Disposable containers and sticks for mixing. Bedding compound has a working time of 20 to 45 minutes depending on product and temperature. Have everything ready before you mix.

The bedding area

For a basic bedding job on a bolt-action rifle, the areas that get compound are: the recoil lug pocket in the stock, the receiver footprint area forward of the recoil lug, and the tang area at the rear of the receiver. The barrel channel does not get compound — you are bedding the action, not attaching the barrel to the stock.

Use a Dremel or chisel to open up the bedding area in the stock — you need enough space for the compound to flow in around the action and create a meaningful layer. Typically 1/8 inch of clearance around the receiver footprint area is sufficient. The recoil lug pocket needs clearance on the sides and front of the lug so the compound can flow completely around it. Removing this material before bedding is what gives the compound room to work.

The pour

Mix the bedding compound according to instructions. Apply it to the stock inletting — not to the action. Press the action into the stock and install the action screws at correct torque. Excess compound will squeeze out around the receiver and may flow toward areas you did not intend. Have a rag with acetone or solvent available to clean up squeeze-out before it cures.

Set the rifle aside and let the compound cure for the time specified — typically 24 hours at room temperature, longer in cold conditions. Do not rush this. Partially cured compound does not provide the dimensional stability that fully cured compound does.

Separation and cleanup

After full cure, remove the action screws and tap the action free with a wooden or plastic mallet — gentle taps, working from multiple directions. If the release agent was applied correctly, the action will come free with moderate effort. If it does not come free easily, do not force it. Work penetrating solvent into the gap between action and stock and wait. Eventually it will release.

Clean the cured compound from the action with the appropriate solvent for the compound used. Trim any flash or squeeze-out from the stock with a sharp chisel. The bedded stock inletting should look like a precise negative of the action geometry — smooth, even, and perfectly matched.

Verification

Reinstall the action and run the layout dye test again. What you should now see: an even, full transfer across the entire receiver footprint and the full face of the recoil lug. No high spots, no voids. If the test shows high spots where the compound has created them — slightly uneven curing or movement during cure — they can be carefully reduced with sandpaper on a flat backing.

Pillar Installation — The Simpler Half of the Job

Pillar installation is less complex than glass bedding and lower risk. The worst outcome of a bad pillar installation is a slightly misaligned screw hole, which is correctable. The worst outcome of a bad glass bedding job is a bonded action.

Pillars are typically purchased pre-sized for specific rifles, or cut to length from aluminum bar stock. The outside diameter matches the screw hole size, and the inside diameter is bored to pass the action screws with minimal clearance.

Installation: remove the action from the stock. Drill out the existing action screw holes in the stock to match the outside diameter of the pillars. This is where precision matters — the holes need to be straight and at the correct locations. A drill press is strongly preferred over a hand drill for this step. A drill guide or bushing keeps the bit aligned if a drill press is not available.

Epoxy the pillars in place with a quality structural epoxy — Marine-Tex or JB Weld work. Apply epoxy to the outside of the pillar and to the inside of the drilled hole. Set the pillar, allow to cure fully, and trim to the correct height so the pillar face is flush with the stock inletting.

After pillar installation, the action screws bear against metal rather than stock material. Torque to specification and confirm the action sits without rocking. If it still rocks — which it may, because pillars address compression rather than fit — glass bedding is the next step.

When Bedding Work Is Not the Answer

Bedding improvements help rifles that are limited by action-to-stock consistency. They do not help rifles that are limited by something else. Before doing bedding work, work through the full accuracy diagnostic sequence — action screws, scope and mounts, ammunition, trigger, barrel contact. Bedding is step seven in the diagnostic hierarchy, not step one.

A rifle that shoots well but inconsistently — groups that vary between sessions without explanation — is a bedding candidate. A rifle that shoots consistently badly is almost certainly limited by something else. Consistent poor accuracy means the same error is happening on every shot — which points to technique, trigger, scope, or barrel, not bedding.

The bedding investment in time and materials is meaningful. Make it when the diagnosis supports it. The layout dye test tells you whether the investment is justified. If the test shows good contact across the full receiver footprint, the bedding is acceptable and the accuracy problem is elsewhere.