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Old 12-01-2008, 06:24 AM
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John Picher's 10-22 Improvements



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Submitted By: Picher

Rev. 8/22/1999

1. Trigger work- these rifles are notorious for having heavy, long, and rough triggers with a large amount of backlash after the sear breaks. Modifying the factory trigger is not something I would recommend to anyone but the better gunsmiths. I wont explain how to dismantle the trigger assembly. If you cant take it apart, dont even think of altering it. However, reassembly is simplified by making a short "slave" pin to hold the trigger and sear together while inserting it into the trigger frame. The pin is pushed out when the real pin is inserted through the trigger frame. A person must have the necessary India and Arkansas knife blade, parallel, and triangular stones plus a fine square vise to help maintain set angles while stoning. Never, repeat never, stone a sear or hammer without setting the proper angles on a machinist vice or using jigs. The way I do trigger surfaces on this rifle involves changing the angles of contact so that the sear becomes the "female" or flat passive surface and the hammer becomes the "male" or rounded surface that glides over the "female" surface. This is opposite from the way the trigger comes from the factory, but it provides a very smooth and consistent pull. I wont get into proper angles or explain further. It is a process learned by reading many books on the subject, including "Pistolsmithing" by Major George Nonte. To you, I suggest buying after-market trigger, sear, and hammer made by any of the better manufacturers such as Volquartsen, Clark, etc. After doing trigger work, I always apply Dri-Slide moly oil to the parts to prevent galling. It is available from Brownells. Remington dry lube spray is probably okay too.

2. After stoning and polishing, surfaces must be hardened to keep them from changing. I use Casenit available from Brownells. An acetylene torch mounted in a vice with a large flame length, a pair of pliers (small needle-nosed locking pliers work good), a coffee can full of cold fresh water, and the open container of Casenit. The portion of the part to be hardened is heated until red, then dipped in the Casenit. If the material doesnt stick to it, heat it again to a brighter red, and try again. Re-heat the part and the Casenit will melt and bubble. Dip the part again and reheat. After about a minute or when convinced that the part is a little hotter than it was before dipping, quickly plunge the part into the water fully and shake it around until cool. Remove the black coating from the steel and look at the part. If the treatment was successful, the part will take on a dull gray appearance. Repeat the entire hardening process to obtain a thicker case over the soft metal. I generally clean off the crud with Break Free and polish the surfaces with a cotton cloth dipped in metal polish.

3. The engagement, or length of pull before firing, can be adjusted more easily. A small machinists or drill press vice can be used to clamp the hammer and if the surface to be stoned is kept very close to the flat vice jaws, the jaws can guide the stone so proper angles can be maintained. Reduce pull length by stoning the rounded surface of the hammer above the notch, making the notch shorter. Length of pull cannot be reduced too much or the safety will not work or the sear can chip off or wear to become unsafe. It can usually be reduced considerably from the original length of pull and can be checked by reassembling the trigger group and trying the trigger pull length, then comparing it to the length with the safety on. The difference is the safety margin. After the length of pull is satisfactory, stone the rounded portion to restore its previous shape, but stay away from the notch. Again, the surfaces should be hardened to keep them from wearing prematurely, but if the hammer notch is not stoned except to remove minor roughness, it may be possible to eliminate the hardening, since the surface to contact the sear already hardened. Further hardening does reduce friction, however.

4. Installing a trigger stop in the trigger requires an electric drill, a drill bit, a tap, and is facilitated by using a Moto Tool with a cutoff disk. I use a #31 drill and 6/48 tap because I usually have a bunch of Weaver base screws around, which I use for the stop screw. The trigger is drilled through the fat part of the metal parallel to where the trigger return plunger presses, but on the opposite side. A hole is drilled on an angle to try to avoid the plunger. Then the hole is tapped. I often use a variable speed drill to tap with. It can be done slowly and reversed to remove chips. It is usually impossible to miss the plunger completely with the full-diameter screw, so I grind the exposed portion of the screw narrower and re-contour the plunger nose to look more like a bullet nose (but having a rounded tip like a ball bearing). Its also good to stone the surface the plunger engages on the trigger to smooth the pull. The screw head is cut off and a narrow screwdriver slot cut in one end with the cutoff disk. The screw is turned into the trigger until it protrudes from the rear surface about 1/16" until assembly and adjustment. When adjusting, dont remove all the backlash. The trigger parts need to fully release to prevent premature failure. I usually turn the screw in until the hammer wont drop when the trigger is pulled. Then, holding the trigger back, unscrew the trigger until the hammer drops, then take another 1/16th to 1/8th of a turn. Apply a drop of locktite to the front and rear of the screw. The screw shouldnt protrude from the front of the trigger, if it does, cut it off. The edges of the hole in the face of the trigger should be stoned or filed smooth.

5. Reducing headspace is important to achieving accuracy. A vernier caliper is needed to measure the depth of the recess in the bolt face where the case rim sits. That recess depth is usually about .055" from the factory. For optimum accuracy, it is usually reduced to .042" by milling. If you are good with your hands, patient, careful, and have a machine vice a machinists square, and a belt or disk sander the bolt face can be sanded down fairly easily. This job can be botched easily, making the bolt face crooked and destroying accuracy instead of improving it. If you doubt your skill, take it to a machine shop and have it planed. If you want to take a chance and you ruin the part, bolts (blue) are available from Brownells for $18.00. I clamp the bolt in a drill press vice so the end protrudes about the amount to be removed, then hold the face against the sander until it measures the proper (.042&quot amount. It doesnt hurt to leave it about .043", but dont make it less than .042" or the gun may fire when the bolt closes. If the top, side and bottom edges of the bolt are a ground very, very, slightly more than the area around the cartridge recess, there will be a more positive contact with the barrel. If one corner, or edge, makes contact first, the bolt may twist slightly upon impact (not good). After sanding, stone the face smooth and polish it.

6. First-shot flyers... They are caused when the operating handle binds the firing pin after the shooter manually cycles the action. There are two modifications that will cure the problem. First, file or sand the sides of the operating handle where it contacts the bolt to create a loose fit... then polish the surfaces. Second, deepen the stake indentations on top of the bolt to restrict vertical movement of the firing pin in its slot at its most forward position. Just leave a little of wiggle room to prevent binding when dirty. Placing a weld in the slot nearer the face of the bolt controls the pin better, but is more difficult to do. In operation, it never hurts to wiggle the bolt handle after releasing it on the first round from the magazine.

7. The rough firing pin edges should be sanded and stoned smooth. The pin is easily removed by driving out the rolled pin using a properly sized drift pin (available at Sears). Be careful not to lose the small return spring in the bolt slot. Check the firing pin indentations in fired cases to be sure they are uniform in depth and location. If they seem wide and shallow and recoil seems to vary while shooting good ammo and shots are stringing vertically on the target, the tip can be stoned narrower. It must not become a knife-edge that can pierce primers. Hot gases (from pierced primers) coming back at you are extremely hazardous to your eyesight. If you are not comfortable with stoning the tip, just order a new pin from Brownells or the factory.

8. The mainspring strut edges are often rough and should be stoned, or sanded, then polished to speed lock time and increase hammer speed. The tip of the strut should also be stoned and polished smooth. To disassemble the unit, just clamp the tip in a vise, push downward on the spring, and the retainer disk can be slid off. When re-assembling, put a little moly oil or Remington Dry Lube on it.

9. Extractor nose- Check the rounded end of the extractor where it contacts the barrel to be sure its smooth, if not, stone it to reduce friction. Often, after reducing headspace, the rifle will stovepipe jam. Thats because there too much gap between the extractor hook and bolt face. The fix may be as simple as holding the forward portion of the extractor in a vise, and heating the rear portion, then hammering it toward the forward portion to reduce clearance. Final filing of the inside rear portion to maintain proper clearance may be necessary. A more involved method is shown under "Extractor Fix" on the Main Page of Rimfirecentral.com. Often a Volquartsen extractor can solve the problem.

10. Barrel face: Check it to see if smooth, if not, grind it smooth and square. A few (1 to 3) thousandths can be removed from the face using a belt sander, but check it before to see if loaded rounds seat fully without pressure. If so, proceed to remove metal slowly and keep cleaning the chamber and checking to see if the loaded round contacts the rifling. If contact is made, it should be very slight so as not to prevent full barrel contact with the bolt. If too much metal is removed from a hardened breech end of a barrel, the bolt can eventually batter it. Be careful! Be sure to clean the bore carefully after working on the bolt or barrel with any abrasives.

11. The face of the hammer and its contact point on the bolt should be stoned to reduce friction when the bolt is pulled back. Roughness may not affect accuracy, but makes it easier to pull the bolt back.

12. Check the barrel crown, if slightly burred, stone the burrs down using a round carborundum stone twirled lightly with the your fingers or use a special brass ball (from Brownells) or a round head bolt in a drill with grinding compound. Be sure to turn the barrel often to make the job consistent. A patch pushed from the breech, almost to the muzzle will limit the amount of crud in the barrel. Push the patch out the muzzle and clean the bore carefully afterward.

13. Drill a 1/4" hole in the rear of the receiver centered about .300" below the top edge of the receiver to be used to clean the bore from the chamber end. Cleaning from the muzzle will often damage the critical crown and last inch of bore.

14. Be sure the scope mount base is attached firmly with Locktite between the base and receiver and on the screws. There can be no movement in the base or mounts, or horizontal stringing of groups will result.

15. After the rifle is reassembled, test fire it with several types of ammo, especially Federal Match 900B, Fiocchi Super Match, Eley Tenex, and a few less expensive brands. If groups are under 1/2 inch and round, youve done a good job. If they string vertically, you may have inconsistency in ignition of the priming mixture. Stringing is usually caused by light and/or inconsistent firing pin strikes. Very hard ammo rims, crud, a weak mainspring, a firing pin that is either not protruding from the bolt face sufficiently, or too wide a firing pin tip can be causes.

16. If groups are stringing diagonally, check the barrel bedding to assure that there are no protrusions, particles, or high spots in the barrel channel. If groups are generally tight, but flyers show up to ruin the group in no particular location, try other makes/types of ammo to find one that the rifle likes.

I hope this helps anyone to get better accuracy from his or her 10/22. Its fun to work on this rifle and see improvements that result from careful work. A clean action, especially the bolt face, barrel face, and firing pin slot are essential to maintaining accuracy. A dirty firing pin slot will result in inconsistent velocities from poor ignition.

Thanks to all who contributed information over the years especially to some great folks on the Internet.

John Picher
 

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