Proper Epoxy Bedding Techniques

There have been many accuracy tricks pioneered by the benchrest-shooting crowd that have been adopted by hunters seeking better accuracy. One of those ideas involves "glass" or epoxy bedding. In the quest for ultimate accuracy and that elusive one-hole group, the benchrest folks learned quite early on that if the wood-tometal fit is not perfect, group size will suffer.

Through the years epoxy bedding has gone through a metamorphosis with many people adding their thoughts and techniques as to how this should be done. I’ve adopted several of these ideas, and each will be detailed here along with why I believe they are important. Preparing the Metal How do we find out if the woodto-metal fit is as good as it needs to be? An obvious clue that it is not would be detectable movement of the barreled action in the stock once the action screws have been backed off slightly.

How about the rifle’s groups? Do they shift? For example, do you have two shots pretty close to one another and then the next two cluster higher, lower, or to one side from the first two? This can be a sign of poor wood-to-metal fit. To begin a bedding job, take the bolt out of the action and set it aside, check the chamber to make sure it is clear, and then remove the action screws. The barreled action should now come out of the stock.

We now need to remove all the parts on the bottom of the action that could collect excess bedding compound. Once the bedding compound hardens and it has found its way around the trigger or safety components, it will be very difficult to remove the barreled action without some wood damage. It’s better to remove these parts. With the components removed, we now have some open cavities and pin or screw holes we need to deal with.

It’s best to plug these voids with modeling clay so they are flush with the outer surfaces of the action. After the bedding has been completed, the clay is fairly easy to remove and final removal of any clay residue in screw threads can be done with kerosene. The use of action-guide pins will maintain alignment of the barreled action in the stock while the epoxy agent hardens. Insert action-guide pins of the proper thread size and wipe all the external metal down with an oil-displacing solvent.

The product I like best for these bedding jobs is Brownells Ac raglas Gel. When mixed, it has the consistency of peanut butter, and stays where you place it. Previously, the liquid form of Acraglas was the standard for doing this type of work, but I find that this type is quite runny and sometimes the non-filled areas need to be redone, which requires a second patching process.

Acraglas still fills my need for those jobs requiring a less viscous epoxy that will run down and settle into place, such as repairing broken or cracked stocks. The Acraglas Gel comes in a kit, along with a release agent that prevents the barreled action from becoming a permanent part of the stock. Brush the release agent on all the areas of the barreled action that fit into the stock where the epoxy will be placed. I do this twice in case I missed any spots on the first coating.

Brushing the release agent over the modeling clay will help with clean-up later. Stock Preparation The bedding areas of most concern in the stock are in the rear tang area and the area around the recoil lug.

When shifting of the barreled action in the stock during recoil occurs, it will affect these areas most adversely. Depending on how the stock grain is structured, the battering caused by an improperly fitted action will cause splitting of the stock, either in the wrist area or along the sides of the stock in the area of the magazine box. I have repaired a pre-64 Model 70 Winchester stock that was split in the area behind the recoil lug.

The split went from the rear tang through the left side of the wrist along the wood grain. The split was a clean one, and by gluing and clamping was repaired to an unnoticeable condition using Acraglas. The action was epoxy bedded into the stock, and for the last 20 or so years has served its owner without splitting again. To ensure that the bedding compound creates a perfect fit, we need to remove wood in the tang area and where the rear face of the recoil lug resides.

With this process, the bedding will stay solid as long as the action screws are backed off when the rifle is put away until the next season. To ready the rifle for the next season, the action screws are then drawn tight, pulling the barreled action back into place. This reasoning was to allow for the changes in humidity that would affect the stock during the summer and winter months.

This loosening and tightening of the action screws has a tendency to compress the wood fibers underneath the bedding compound, causing the bedding to eventually go sour. Not a good thing. The next phase in the process of epoxy bedding has typically been the placement of nylon pillars installed perpendicular to the hollow capil laries in the stock wood to prevent fiber compression when the action screws are tightened.

The current method, and the one I prefer, uses aluminum sleeves through which the actions screws fit. This method doesn’t add any more holes in the stock, but does require that the action-screw holes be opened up to accommodate the sleeves. I use 3/8-inch-diameter sleeves that I make myself whenever the action style I’m working with allows it. When dealing with the small-diameter tang screws on some of the Remington models, I adjust the outside diameter accordingly.

For those action screws that are 1/4-inch in diameter, the 3/8-inch diameter aluminum sleeves with a .265-inch through hole support the action quite well. As I’m doing the lathe work to turn these sleeves to length and drill the through hole, I’ll also turn a groove along the outside diameter of the sleeve as though it was a thread. This spiral groove is done at nine turns to the inch and .020-inch deep or just deep enough to capture some of the epoxy and create a more firm bonding of the sleeve to the stock wood.

Setting the Epoxy It works best for me to use a piloted flat-bottomed, counterbore tool in my drill press to open up the action screw holes in the stock. A 1/4-inch-diameter pilot mounted in the counterbore tool follows the action screw holes, while the 3/8-inch diameter cutter enlarges the screw holes for the

sleeves. It’s important that the sleeves are faced to the correct length for each application so they maintain the distance from the inside face of the bottom metal to the inside bottom face of the barreled action. After the action screw holes have been opened up to 3/8 inch, the outside of the aluminum sleeves are then coated with epoxy and installed into the stock.

The Acraglas Gel will hold the sleeves in place, but to prevent any movement, I’ll place apiece of cellophane tape over the top and bottom of the sleeves to ensure they stay where they’re supposed to until the epoxy hardens up, usually overnight. After the epoxy has cured and the sleeves feel solidly placed, the barreled action is tried for fit with the action-guide pins installed in the action.

To remove the stock wood in the tang and recoil lug areas that will be replaced with bedding epoxy, I find it best to use a 1/8-inch-diameter ball rasp in my rotary tool. This tool I use has a flexible shaft with a pencil-style hand-piece that’s very easy to control and direct. Remove material around the aluminum tangs-crew sleeve and undercut the stock sides slightly where the tang fits.

Try not to go up and beyond the top edge of the stock or the bedding compound will ooze up and over the top edge of the stock and ruin the job. I usually remove wood to a depth of around 1/8 inch and leave the wood in a roughed-up state so the epoxy bedding will have an effective bonding surface. For the recoil-lug area, we need to remove wood around the sleeve for that action screw using the same diameter rotary ball burr.

Again, undercut the sides of the stock, staying at least 1/8 inch below the top edge of the stock. Move the face of the stock, where the recoil lug would normally rest, back about 1/8 inch by removing the wood in this area. The bedding compound will fill this void and create a solid surface for the recoil lug back face, eliminating any shift during recoil.

To create a support pad for the chamber end of the barrel, I’ll rough out that part of the stock-barrel channel in the forearm to a depth of 1/8 inch or so and around 1-1/2 inches forward of the recoil lug cutout. For sporter-weight barrels, a dampening pad is roughed out 3/4 inch back from the forearm tip end. The intention of this pad is to dampen the harmonic waves that affect the thinner sporter-weight barrels after the bullet leaves the muzzle.

On heavy varmint-weight barrels, this is optional, as the nodes are not as extreme in the heavier barrels. Mix up your bedding compound according to the instructions provided. I normally use a bit of brown dye sold explicitly for this purpose on all dark walnut stocks, but there’s no reason the epoxy bedding compound can’t be used as is. The trick to mixing this compound is to mix enough for the job. Mixing less than you need causes more grief than mixing a bit too much.

As insurance, it’s a good practice to place masking tape along all the upper edges of the stock where the bedding compound will be placed. In the event any compound does ooze up and onto the stock finish, it will be quite messy. The masking tape will aid with cleanup later on. Poke the bedding compound into place where you removed the wood, striving to avoid getting any into the inside of the aluminum sleeves. Once you feel you have enough compound inserted into place, install the barreled action into the stock.

To force the barreled action into place, I use two Jorgenson woodworking clamps. These are wooden clamps with a turn screw controlling both the top and bottom jaws. With reasonable force, they will not damage the stock. The clamps are left in place until the bedding compound hardens up, usually overnight.

Conclusions Once the epoxy bedding compound has cured and the clamps have been removed from the barreled action, I give the ends of each action-screw guide pin a sharp rap with a hardfaced plastic mallet to shock the action loose from the stock. Any of the leftover bedding compound will give you a good idea when the compound has hardened up thoroughly.

The only task left now is to clean up any bedding compound that has entered the stock cutout for the trigger, magazine box, and the area where the bottom of the recoil lug rests in its cutout. For best accuracy, we want the bottom of the recoil lug to free-float in the stock. ■