I read Gunsmoke Engineering's rebuilding article and it was a godsend to have a walkthough, but I found several significant deficiencies in their original instructions, so I started doing my own version with extensive additions. I haven't given it to anyone until now, and was intending to send it to Gunsmoke if they wanted to post it, but wanted to try it again from scratch again to see if my instructions were okay (its a technical writer thing...), but my mags don't seem to go down as much anymore, so this has been forgotten on my hard disk for over a year now, and I am hesitant to post without comparing to see if I have included any significant amount of text from Gunsmoke, so I can "give away" any rights to it, but I don't think there is a harm to posting it for non-commercial purposes, but don't "lock it up", as I expect to make revisions in the future, and I'm too tired to work on it more tonight .....
(Note: It will probably look a lot better if you copy it into Word or such and format it for printing. It lost formatting when I copied it in here....)
Servicing Ruger 10/22 Magazines
10/22 commonly encounter feeding problems due to accumulating fouling, deposits from waxed bullets, internal component wear, and/or improper factory assembly. I find they commonly develop sufficient interior fouling to start misfeeding after a few hundred rounds with wax-lubricated slugs and internal plastic-on-plastic wear (which looks much like galling). The Ruger 10/22 manual does not recommend disassembly, but does provide a magazine assembly illustration on p. 17. The seven parts (with Ruger nomenclature and my description / simplified terms) are:
Magazine Shell -- the plastic body of the magazine
Magazine Cap -- the plastic rear end panel you remove to open/disassemble the magazine
Magazine Throat -- the metal feed lips which hold the cartridge to be fed into the chamber
Magazine Rotor -- the plastic cartridge feed mechanism which rotates each cartridge into place for feeding
Magazine Rotor Spring -- the metal spring which provides the tension to rotate the rotor
Screw -- the metal ( 9/64" socket head cap) screw which holds the magazine together
Cap Nut -- the hexagonal-head nut which fits into a hexagonal recess on the magazine cap (which closes the rear of
the magazine) and the mates with the screw to hold the magazine together. It also retains the end of the spring. The cap nut can be rotated (once you learn the trick of backing off the screw) to adjust the spring tension on the rotor.
The magazine can be serviced (and improved) as follows:
1. Start by clearing the magazine of any cartridges. Jammed cartridges can usually be persuaded to feed with something similar to a matchstick or swizzle stick (something that will not mar the interior), and they can then be pushed forward out of the magazine lips.
2. Study the assembly so you know what is in the front and rear, and how the feed lips ("magazine throat") should look when properly assembled. It is strongly recommended you keep the 10/22 manual illustration of magazine assembly on p. 17, and/or a spare, factory-assembled magazine on hand for comparison during reassembly.
3. I use "Liquid Paper" (or other convenient source of fast-drying white paint), to put a small dot on the hexagonal spring retaining cap on the rear of the magazine at a spot showing its alignment to the hole used to align the metal feed lips ("magazine throat") with the hole on the rear panel ("magazine cap") on the plastic magazine shell. If you confuse easily, you could also put alignment marks on the points where the feed lips have a small boss or stud which aligns with holes in the front and rear of the magazine near the feed slot, but this should not be necessary.
4. Begin disassembly by backing out the socket head cap screw at the front using a 9/64" Allen wrench. It is usually in pretty tight, so you need to hold the mag firmly, possibly with gloves or a towel to protect your hand. When it has been loosened [about 2 turns -- almost out], push the screw back SLOWLY, to push out the six-sided cap nut on the other side of the mag. This is going to want to get away from you and spin around real fast to release spring tension, but if you grab it carefully with fingers or a wrench, you can count the number of turns it takes to relax the spring preload. The manual says 1-1/4 turns (this is impossible with a six-sided nut, so 1-1/3 is more realistic, but this feature allows some "tuning" of spring tension by the owner). Keep your finger on this piece to prevent loss.
5. Move the cap nut slightly back from its seat, carefully noting how the end of the spring fits into a tiny hole in the cap nut -- you will need to replace the spring into this hole upon reassembly. Set the cap nut aside in a safe place.
6. Remove the magazine end-cap -- the back-side of the magazine -- and set aside.
7. Pull out the magazine rotor, keeping track of how it is positioned so you can put it back later. Notice how the one long vane on the rotor is pressed up against the cartridge feed lips by spring tension. This is critical to reassembly. Remove the rotor spindle. Note where the rotor (and cartridges) produces wear marks on the inside of the magazine body. If you are using waz-lubricated cartridges, these wear marks will be coated with wax, which can be gently scraped off with a fingernail or some non-marring piece of wood or plastic.
8. Slide the cartridge feed lips out of the magazine shell. Note the larger locating stud engaging a partially obscured alignment hole at the front of the magazine shell and the smaller stud engaging an alignment hole at the rear of the magazine shell. Note the different shape of the feed lips front and back, and the different cut-out on the inside, and how it fits into the shell at an unusual angle. Set the feel lips aside for cleanup.
9. Clean up everything with your preferred cleaner (I use SimpleGreen and alcohol, but Hoppes and other solvents also work well, as long as you leave things clean). Dry everything off. You may coat the spring with a very light coat of oil if you wish, but keep oil off everything else. Oil in the mag itself just gathers dust and fouling.
10. Notice the wear pattern on the inside of the magazine shell. I find wax from bullet heads which needs to be scraped out, and plastic-on-plastic wear on the inside. I found the buffing wheel supplied with my Dremel tool to be a prefect fit to the inside of the magazine shell, and (using the mild red rouge abrasive supplied with the accessory kit) buffed the inside of the magazine with light, smooth, gentle strokes until it was a lot slicker than new. Do not press down too long or too hard, as heating up the plastic excessively could ruin the magazine. This polishing should give the wax and fouling less opportunity to collect. I also gently polished the long vane on the rotor, which was rubbing and galling the inside of the mag shells, the most likely cause of the jamming. When you are done, you will have to thoroughly clean out all residue from the rouge abrasive, so a second cleaning is in order. I finish up by doing a wipedown using a cloth dampened with alcohol.
11. Clean and inspect the feed lips for residue and sharp spots which could cause feed problems. Replace the cartridge feed lips back into the top of the mag shell. The feed lips fit into the magazine shell tilted to the right, with the large stud or boss fitting the alignment hole in the front of the mag shell and the more open end of the slot (with the rounded feed lip ramp) opening toward the forward portion of the mag shell.
12. If you completely removed the spring, make sure that the end of the spring with the right angle bend engages the hole in the rotor. The spring is the only thing I would consider lubricating in the magazine, but it really doesn't seem to need it. You should have no oil in the rest of the mag, as it will only collect grit and fouling.
13. Reinstall the rotor spindle and rotor/spring into the mag shell, with the more open end of the vanes forward and exposed spring facing to the rear. Remember how one of the vanes on the rotor is longer than the others? Make sure this vane will be held against the cartridge feed lips (by spring tension, once applied), and the ends of the rotor engage the shoulders at the front and back end of the magazine shell.
14. Put the rear end shell cap in place, verifying that the rotor spring sticks out through the hole in the center and that the small alignment stud on the cartridge feed lips engages the hole in the shell cap. Hold the rear end shell cap tight to the mag shell during reassembly.
15. Engage the protruding end of the rotor spring in the small hole in the shoulder of the spring retaining cap. Verify the full length of the spring beyond the bend enters the hole. It usually goes right in if aligned properly, but is a bit like threading a needle, but you cannot see the hole while you do this, so you need to know where it is. You can support the end of the spring (with a small screwdriver or needle nose pliers) when engaging the spring end in the cap hole, but this should not be necessary, but it takes a bit of fiddling to get it in.
16. Thread the screw through the front of the mag shell and rotor and start the screw into the cap nut about 1/2 turn (no more).
17. You need to tension the spring by winding the spring retaining cap in a clockwise direction. Start by taking up the excess slack in the spring (the long rotor vane should be pressed against the cartridge feed lips, visible through the feed lips slot). Note the spring retaining cap has six flat sides on it. Align the paint mark you made so you know how much preload you are using (this can be adjusted, if required). With all spring slack removed, turn the cap one full turn, and press it into place to hold it from springing back. The retaining screw tightens as you preload the spring, so it may not go a full turn if you have it too tight, but you can move it incrementally if you watch the alignment mark.)
18. Now BACK OFF the screw one full turn. Then, very carefully press the retaining screw so the six-sided spring retaining cap moves out enough to grab it. (You can use a wrench, or do this with strong fingernails.) Do not push it clear of the recess in the end cap until you have it under control, or the spring will cause it to unwind rapidly. Now add a second full turn of tension, then press the six-sided spring retaining cap carefully into its restrained "home" position in the end cap. You can now fully tighten the screw.
19. Check the follower tension: it should be sufficient to snap smartly back when you depress the follower with a drift or screwdriver. You can also compare tension to the still-assembled comparison magazine. If it is not correct, you can loosen the screw and re-tension it again. The 10/22 manual says 1-1/4 turns (impossible with a six-sided nut), Gunsmoke Engineering's post indicated tightening by 4 flats to get proper tension, while my experience is 1-1/2 to 2 complete turns, or 9 - 12 flats beyond the spring rest position (but I fire at a range which only allows five rounds loaded, so I almost never load 10 rounds). You can adjust to what works best for you.
I hope this helps. Direct corrections/revisions to <firstname.lastname@example.org>