10-22 Bedding and Accurizing Techniques by John Picher - RimfireCentral.com Forums

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Old 12-01-2008, 07:24 AM
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10-22 Bedding and Accurizing Techniques by John Picher



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Submitted By: Picher

Rev. 8/18/2001
Editor Note: Some of these modifications may be too difficult for some readers. Attempt at your own risk as I will not be responsible for any damage you may do to your rifle. Results may vary.

Before bedding, I recommend that the barrel be epoxied to the receiver to eliminate accuracy robbing movement. To do that, remove the barrel from the receiver, clean all contact points with alcohol, and apply a stud-mounting air setting epoxy liquid such as Permetex stud mount, red Locktite, or bedding epoxy to the barrel extension that enters the receiver. Re-assemble, using the cap screws and dovetail block. The barrel mounting dovetail block should also be epoxied. That should eliminate movement that destroys accuracy. While you're at it, Locktite the scope mount bases and screws.

1. The barrel channel is the most important area. The first 3 to 4 inches of barrel starting just beyond the barrel attaching screws should be bedded under the barrel and up to about 1/8" of the top of forend. After the bedding material is set, this area should be the primary pressure point as the action screw is tightened.

2. The barrel can be free-floated the rest of the way toward the end of the forend, or (after the initial bedding job) a pad of bedding can be added within 1 1/2" of the forend tip with about 10 pounds of upward pressure on the barrel. A small wedge can be made to fit between the barrel and end of the barrel channel. Clamp the forend in a vise and using a fish Deliar scale pull upward on the barrel near the forend until the 8-10 lbs is achieved, then push the wedge in to hold it in place. Tape the wedge to the barrel so it can hold the gap at the proper amount as the bedding pad sets up. Be sure to check that the barrel is centered in the channel. If making a new stock wait until the forend pad is installed before establishing final clearance of barrel to sides of barrel channel, since the barrel will be somewhat higher in the stock as it approaches the forend tip.

3. When free-floating the barrel in the forend, be sure to keep all wood well away from the metal... 1/16" is not too much. People think that a barrel is free-floating if you can force a dollar bill between the barrel and bedding. That's not enough for two reasons: first, because barrels vibrate when fired, and second, because wood swells and warps with humidity. Poor bedding and inadequate free-floating generally results in diagonal stringing.

4. The next area to be concerned about is the action screw and barrel lug area. This area should not be tightly bedded. Just be sure to leave a small pad of wood, perhaps along the front edge of the magazine well opening to hold the action at the proper height during bedding. I like the barrel to become the centering device because it is rounded and will self-center as the action screw is tightened. Its also important that pressure be applied to the barrel to make its vibration consistent. I basically take my Dremel tool and router bit to remove about 3/32" everywhere the metal comes in close contact with the wood, but only about 1/16 at the edges of openings such as the top of the forend and around the action. Then, before bedding, I place two layers of masking tape over the barrel bottom of the barrel attaching block and matching receiver casting (sides and bottom). Then I make an "x" with a knife over the action screw hole to allow the screw to enter the receiver. When the tape is removed after bedding, it assures that the barrel receives the greatest pressure when the action screw is tightened.

5. Wood inside the receiver area of the stock is routed lightly to roughen it to better accept the bedding material. The bottom edge of the receiver should have about 3/32" of bedding, but leave a little pad of wood at the rear bottom to hold the receiver at the right height while bedding.

6. The rear of the action is a special place. The top 1/2" must not be bedded to allow the action to pivot upward when removed. A gap of about 1/16" is usually present from the factory. Just place some modeling clay or electrical duct seal prior to bedding to prevent the bedding material from squeezing upward into that area. I usually pull it out with a wire about the size of a paper clip before trying to get the action out of the stock. The bottom 1/2" or so at the rear of the receiver is routed out about 1/8" to give a solid recoil pad. Bedding the sides and rear of the receiver is different from most recommendations. (A lot of people mostly bed the barrel tightly in bedding compound, sometimes using an additional stock bolt in the forend tip, then let the receiver float free. They also use a cantilever scope mount attached to the barrel. Some also make a large bedding block that may surround the barrel and bed it into the stock as the only contact point. That supposedly works too, but I haven't done it.)

7. The rear of the trigger guard should also be bedded to stabilize the trigger assembly in the receiver as the pins get loose from assembly/disassembly over time. Rout out about 1/8" just behind the trigger assembly and around the radius of the metal. Keeping the assembly in perfect alignment with the receiver is said to promote consistent firing pin strikes.

8. The action screw area is important. The ideal method is to install an aluminum pillar from the brass escutcheon just short of the receiver. Another way is to drill out the hole to allow about 3/32" of bedding material around, but not touching the screw! The screw needs to have a heavy coat of release compound, and sometimes I place a soda straw around it to keep bedding material out of the threads, etc. This screw is smaller just below the threads to allow it to remain in the stock when unscrewed from the receiver. That poses a problem when bedding because bedding can get into the area and keep the screw from backing out of the metal. The straw works pretty well and if left a little long will crush as the screw is tightened. After removing the action from the stock, drill out the area around the screw hole to eliminate any contact between the screw and stock except at the escutcheon. Screw contact with the stock hole is a destroyer of accuracy, especially in hard-recoiling guns.

9. The next thing to consider is use of modeling clay or duct seal. It should be placed in every notch or hole in the receiver that would allow bedding to lock the action to the stock. Areas around the barrel lug, barrel cap screw ends, etc. Also, use masking tape or clay to seal openings where the bedding material can find its way into working parts of the trigger, etc. The area where the front of the magazine well fits against its opening is important to place the clay, because that is a critical pivot area that must not receive bedding or the action cant pivot upward to be removed. Also, you can place a dam of clay in the barrel channel to keep the bedding material from running toward the muzzle.

10. Bedding material choice has some importance. Some people swear by Devcon. I like Brownells Acraglas, but add some flock that I cut up (into 1/4" squares about 1/8" thick) with scissors from fiberglass batt insulation. Brownells also has good release agent. Apply two coats to all metal parts that could come in contact with the bedding material, including the exposed areas above the stock. Place masking tape over the stock adjacent to the openings. After adding a small amount of dye to color the bedding, and adding in the glass flock from the kit, I add some of my flock to thicken the mixture a little to keep it from running out of the action area. Its still a little runny, though, to allow good absorption into the wood. That strengthens the bond and toughens the wood. Follow Brownells instructions very carefully. Uncured Acraglas can be removed from the outside stock and metal surfaces with white vinegar on a cloth.

11. Place the bedding material into the stock recesses to allow for some squeeze-out, but don't worry if there are a few air holes. Unless they are under the barrel or behind the receiver, they probably wont matter in a light-recoiling gun.

12. After allowing the bedding to set up so its not tacky to the touch, say about 4 hours, I loosen the action screw to make sure I can remove it and check to see if the bedding material is hard enough to keep from deforming if the action is removed. If not, just re-tighten the screw. If it is, remove the screw and rap the bottom of the barrel near the end of the forend a few times with a rubber hammer or piece of soft pine to break the seal. Its better to remove the barreled action too soon than too late. It can get "glued in" if you wait too long.

13. After removing the action from the stock, the work is not completed. I like to finish off the material uniformly at the end of the barrel pad by routing a clean end. Next I sand the material to relieve barrel bedding contact down about 1/4" from the top of the forend. Its the bottom third of the barrel that should be cradled anyway. Any contact at the top of the barrel channel can potentially cause uneven return to battery.

14. Rout or drill out the screw hole to keep the screw from contacting the stock except at the bottom. Rout areas of contact around the very front of the receiver. Remember the barrel is the centering device in that area, and a small gap is needed between the barrel lug assembly and the stock. I really don't know if that would cause major detriment to accuracy, but feel that the rounded barrel and its strong pressure in its stock receptacle are the keys to long-term accuracy.

15. Use the router or a wood rasp to clean up non-functional bits of bedding material squeezed out near the receiver recess, etc.

16. After cleaning up the metal parts, removing clay, masking tape, and cleaning off release compound (Hoppes #9 works good for removing release compound), re-assemble the rifle and tighten the action screw fairly tight but dont crunch it because the bedding is still a little soft. Dont shoot the rifle for another 24 hours. Take the action out of the stock before going to the range and check everything one more time, be sure there are no small chips or anything that will keep the action and barrel from mating perfectly with the stock. It doesn't hurt to apply a little car wax to the barrel bedding at this point and reassemble, tightening the action screw fairly tight.

17. Try shooting with the barrel free-floating, but if it doesn't shoot the way you like, try the forend tip pressure point discussed previously.

John Picher
 

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