Wood rifle stocks that swell and shrink due to the climate can lead to varying accuracy. Bedding your rifle can prevent variations and improve consistency and accuracy. Rifle bedding is not just intended for wood rifle stocks though, and as we have found, bedding rifle stocks and chassis made from any other material like aluminum or carbon fiber also benefit from good rifle bedding for the specific action.
Not only does it keep the rifle consistent in pressure and fit in the rifle stock, the rifle bedding also ensures minimal if any point of impact shift when removing and re installing an action from a stock or chassis.
For a rifle to shoot consistently accurate, the steel parts (rifle action) must fit snug in the stock, touch (or not touch) in the right places and not be under tension at all when the locking screws (action bolts) are tightened. Wood rifle stocks that swell and shrink due to the varying humidity of the environment, or oil-soaked stocks can cause the steel to contact the stock in places where it should not. When the shot is then fired, the steel does not react in the same way every time and the result is often varying accuracy.
To ensure that the action fits snugly in the rifle stock, it is advisable to bed the gun. This means that some type of epoxy is placed in the barrel channel and the part where the action rests, the action screws are then tightened again while the epoxy is still wet. The epoxy then takes the shape of the bottom and the sides of the action and guarantees that the stock and steel fit well.
Although I recommend that a competent gunsmith perform this task, it can be done very successfully by anyone with the necessary precautions. Usually, an epoxy, mixed with a hardener and sometimes steel / aluminum filings, is used as packing material and rifle bedding compound. The most important properties that the epoxy should have are shrinkage by less than 1% when dry, it must also be strong, very hard, non-compressible and resistant to firearm oils and solvents. It should bind very well to the stock. Because wood swells, shrinks, and even distorts, it usually helps a great deal to bed any wooden stock with epoxy, as it also seals the wood against moisture on the inside. Even synthetic stocks can benefit from bedding, because sometimes the integration for the steel is not done properly and then the action is under tension when the bolts are tightened. An excellent product is Devcon Steel Putty. The “putties” are less runny than liquid types of epoxy, which makes them easier to work with.
When bedding rifles, remember to cover everything you don’t want the epoxy to stick to. Fail to do so and you are going to struggle to separate the steel and the stock. So a good rifle bedding kit should include the epoxy or steel putty, masking tape and then petroleum jelly to prevent it sticking anywhere you do not want it to.
The method that usually produces the best results is to bed only two areas of the action, namely at the tail (the very back of the action, where the rear bolt fastens) and the recoil lug (near where the barrel and action bolt together and the front screw fastens). The middle part of the action is therefore free. This is called pillar bedding. (See photo 2)
For most rifles, a free floating barrel works well – only the first 40 to 60mm of the barrel (the fat part also known as the Knox shape) is then bedded. Before bedding the rifle, remove some wood from the barrel channel to ensure that there is at least a 0.5 to 1mm clearance between the barrel and the stock. A cardboard business card should be able to slip in comfortably between the barrel and the stock. In some cases, however, a very thin barrel may shoot more accurately with a pressure point below the barrel near the front of the stock or the forestock. Synthetic stocks with a slack forestock that easily bends or deforms can be made firm by putting a 6mm diameter steel bar in the forestock and fixing it with epoxy. Of course still with a gap so the barrel free floats.
The recoil lug must only be bedded at its rear. Keep any epoxy away from the sides. There must be clearance between the steel and the stock so that the steel is not pinched by or pressed against the stock when shooting.
- Use a sturdy workbench on which a bench vice is mounted. Cover the jaws of the vice sufficiently to prevent the stock from being damaged if you clamp it in it. (See photo 1)
- Remove the rifle scope, rings, trigger (only if you are comfortable with it), magazine box, feed plate and spring. Now clean and remove all oil from the action / barrel section, denatured alcohol works well for this.
- Measure the thickness / depth of the stock material at the holes of the two locking screws / bolts in the stock. Use a soft drink straws that fits slightly loosely over the shafts of the bolts and cut a section to the length of the above measurements for each bolt. Store these for use later.
- As already mentioned, remove material from the barrel channel until the barrel hangs freely. Use any round pipe which fits into the barrel channel, wrapped with sandpaper. It helps to rotate the stock 180 ° in the bench vice grip regularly during the process.
- On the parts of the stock as shown in photos 2 and 3, about 3 to 5mm thickness is removed from the stock material. Also, remember to remove material where the recoil lug will press against. Small portions of material can be left at the edges of the stock to prevent the action from sinking in too deeply into the epoxy during the packing procedure. Aluminum pillars can be put in the holes of the bolts (after the holes have been drilled bigger) to prevent the stock from compressing when the action screws are tightened. Pillars can also be formed with epoxy. The holes for the action screws can be drilled with a 13mm drill bit. However, trying to make pillars of epoxy is easier said than done so beginners may not have to tackle it.
- To ensure that there is a clearance between the stock and the steel where the two should not touch each other, apply one or two layers of masking tape to the steel (this will only work if you have removed sufficient material from the stock ahead of time to make room for the masking tape). Remember only the back of the recoil lug may touch the stock, as well as about 25mm of the action right behind the recoil lug. Also, the tang should not press the stock / epoxy anywhere else except at its bottom. (See photos 4, 5 and 6) The parts in blue are where there should be a gap of 0.1mm or more between the epoxy and steel. Parts in red are where there is full contact between steel and epoxy.
- The trigger is tightly wrapped with electrical insulating or masking tape. Any further parts or openings within which there should be no epoxy are filled and finished with modeling clay. The neater and more thorough this task is done, the better the final bedding looks and the easier the action and stock will separate later. Also use clay to fill even the smallest holes and form the contact surfaces to your liking. Crumpled up pieces of paper can be pushed into large openings such as the magazine opening and chamber and then sealed over with the clay. (See photo 7) Remember, when the action is placed in the stock, the epoxy is forced into even the smallest openings under pressure.
- Shape walls with clay to limit the flow of epoxy as shown in photo 8 and others, shown in green. Test by fitting the action in and out of the stock until you are satisfied with the walls working and fit.
- To ensure that you have a barrel in the center of the barrel channel after the bedding, wrap insulating tape around the barrel just short of the end of the forestock. Wrap it thick enough that the barrel is lying down centered in the barrel channel without lifting it higher out or placing the barrel under tension when the action is tightened down.
- Confirm that you are 100% satisfied with your preparation. Gently rub shoe polish (the everyday type from the tin) to ALL parts that the epoxy should not stick or bond to, including the clay, masking tape, bolts, and so on. Rub up a bit and repeat. Wrap any engraving or patterns on the forestock and pistol grip with masking tape to prevent any epoxy leaching from getting into it.
- Place the trigger guard / magazine plate in position and attach it to the stock with masking tape. Put the screws in place and also tape the masking tape over their heads to prevent them from falling out. Slide the correct length of straw that you have stored over each screw shaft to prevent epoxy from getting to them. Clamp the stock horizontally into your vice grip so that you still have access to the screws from below. (See photo 9)
- Mix the epoxy EXACTLY according to the manufacturer’s instructions. Usually it works well to weigh the quantities. Roughly about 100 to 150 grams of epoxy is usually enough for the average rifle. Rather mix too much than too little. Use a kebab stick and gently work the epoxy in around the locking screws up to the trigger bar / magazine plate (if you want to make epoxy pillars). Be careful not to get any epoxy on the threads of the screws and keep the epoxy level below the threads. With that done, pour enough in all the other parts of the stock that need to be filled.
- Get someone to help now – lower the action / barrel SLOWLY into position while your helper is ready to remove the masking tape from the screw heads and gently screw them in. Let them take lightly before screwing them in further. Be very careful that no epoxy ends up in the thread or in their holes. A hole full of epoxy prevents the screw from rotating in to the correct depth and therefore the action will be too high in the stock.
- Tighten the screws one by one slowly until the stock and action alignment is correct. Usually this is when the top edge of the stock and the action’s loading port are on one level and align the middle of the barrel with the top edge of the stock. Do not over tighten the bolts otherwise you can again put tension back on the action.
- Remove the excess epoxy that is peeling out and leave the rifle for about two hours. Slightly loosen and re-tighten the screws to ensure they do not bind to the epoxy. Be careful not to push or strain the stock or action. Scrape off excess epoxy so that it it flush with the stock’s edges and wipe clean. Repeat the process after two hours and then allow the rifle to rest for 72 hours so that the epoxy can harden properly.
- Unscrew the screws and remove the action from the stock. Wiggle the action upwards from the stock with small movements. Work slowly and carefully. If necessary, use a rubber hammer to lightly tap the barrel just in front of the stock. If the stock and steel are difficult to separate, place the gun in a freezer for an hour or two – the wood, steel and epoxy shrink at different rates and make the separation process easier.
- Remove all masking tape and clay, clean the steel with thinners where necessary, then lightly oil it and put everything together. Tighten the screws at 40 inch / pound (4.5 Newton meters). It’s about as much as an average man can tighten a screw with a screwdriver with one hand.
- Allow the epoxy to set for another week before firing the rifle.
- If the rifle has a thin barrel and does not want to group with a free-floating barrel, it can help to make a pressure pad below the barrel near the front of the stock. Clamp the gun upside down in the bench and hang a weight of 2kg at the end of the barrel. Cut out thin cardboard slips that can be slid in near the front of the stock between the barrel and barrel channel until it fits snugly. Remove the action from the stock and form a dam for the epoxy near the front of the stock with clay. Apply shoe polish to the barrel and assemble the gun with epoxy and the correct number of cardboard strips as spacers. The epoxy will form a pressure point that places approximately 2kg of upward pressure on the barrel. The disadvantage of a pressure point is that the impact point of the the bullets moves if upward pressure is applied on the fore end of the stock or if the stock is distorts due to varying climatic conditions.
Now go out with your newly bedded rifle, and shoot shoot shoot.