Here's the skinny for BX-25 magazines (also applies to most other high capacity 10/22 magazines).
Let's start with a factory 10 rounder ... these are rotary magazines where the rotor has a "slot" for each cartridge and an adjustable clock spring. When the tension is set where it is not too tight when fully loaded and not too loose with just one round loaded, they feed amazingly well.
BX-25s are NOT a rotary magazine, rather they are "in-line" that use a non-adjustable ribbon spring and a follower .... totally different than a rotary magazine. Ribbon springs are quite unique because they apply just about the same tension on the follower from the first round to the last round. Herein lies the problem. Any internal friction between the magazine body and the follower, the spool, or the ammo itself will create more friction than the ribbon spring is capable of overcoming. If the cartridges don't slide up properly, they won't feed properly. To compound the issue, 10/22s are "blow back" operated semi autos that blow a lot of powder residue back in the bowls of the gun and of course in the magazine body too. Often times a BX-25 will work fine on the first couple range trips but will eventually build up enough crud in the follower channel where friction is increased beyond the tension capability of the ribbon spring.
Fortunately, there is a good solution that will keep BX-25s running pretty much trouble free .... sounds more complicated than it really is. This also applies to other similar magazines that can be taken apart. Lay the BX-25 on the left side where you can see an Allen head screw at the top and bottom. The words "25 Shot" should be visible near the top of the magazine. Use a 3/32" Allen wrench and remove both screws. The bottom screw has a small hex nut that will fall out on the bench when the screw has been loosened enough. The shorter top screw threads into the metal top end of the magazine and does not have a nut. Set the screws and nut aside then lift the top clamshell magazine body straight up to separate the halves. Locate the ribbon spring and spool .... it is red and looks like a donut. The tip of the ribbon spring has a holding stud. Carefully lift the spool and ribbon spring straight up and remove it from the body. Remove the red plastic follower. Lift the metal top section straight up and remove it from the body. The magazine is now totally stripped.
Take a look inside the left half (the side WITHOUT the 25 SHOT marking). You will see a track with two guides in the body that extend the full length, plus a front and back track surface. Grab the red magazine follower and hold on to the extended shaft then place the follower in the track. Grab a couple 22 LR cartridges and place them on the top end of the follower to see how the cartridges slide on the tracks. As you slide the cartridges with the follower, you will note ... the cartridge case slides on the rear guide and the bullet slides on the front guide. Further, the nose of the bullet drags on the front track and the case rim drags on the rear track. All the surfaces that are touched by the case and bullet must be exceptionally clean and dry. It is common to see casting marks and slight imperfections in the cartridge track. These must be removed or cartridges will gag and not feed properly. 400 grit wet sandpaper works well for removing casting marks ... just don't overdo it or you will make things worse instead of better.
Any bullet lube or powder residue will increase friction to a point where the follower will NOT slide freely. Clean the inside of the left body half with Hoppie's #9 solvent until it is totally free of all powder residue and bullet lube. Wipe it dry with a clean white cloth. Do not use any solvent such as brake cleaner or carburetor cleaner because it will eat the plastic. Do not use any oil in the track or it will attract powder residue and make the follower bind up. To help reduce friction, you can apply liquid car wax to the track and guide surfaces, then buff off the excess after it dries. You can also use Frog Lube ... it works the best!
The right clamshell also has a track but it is for the ribbon spring spool. If you lay the ribbon spring spool in the track, you can see the ends will slide on the single guide and the outside of the spool will drag on the front and rear track. Again, these surfaces must be clean and free of any casting marks or imperfections that might impede movement of the spool. Same drill .... use liquid car wax or Frog Lube to smooth up all contact surfaces.
Last is the metal top section. Make sure the feed ramp is smooth ... no imperfections. Check the top feed lip ... often they have a sharp edge that tends to grab the case and scratch it. This can impede feeding. Clean the metal top section thoroughly but do not oil it. Clean and dry only!!!
Once the magazine has been thoroughly cleaned and "friction proofed" with car wax or Frog Lube, it's time to reassemble. Lay the left half of the body on the bench (the side WITHOUT the 25 SHOT marker). Set the metal top piece in place. It will only go in one way because the front has a much larger extension than the rear. Lay the red magazine follower in the track with the extension shaft pointed up. Slide the follower all the way to the top. Place the red ribbon spool on the follower shaft then pull the spring out just a little until you can fit the stud in the slot of the metal top piece. The ribbon spring has to follow the contour of the slot so make sure it isn't in backwards .... the coil end should be on the right side. Lay the other half of the body in place. It should snap together where everything fits with no gaps. Insert the top screw (the shorter one) into the hole and snug it up with an Allen wrench. Do not over tighten the screw or it may strip the threads. Insert the bottom screw in the hole then insert the nut on the other side. Snug up the screw with the Allen wrench and you are finished.
Remember a few key issues ... the cartridges must slide freely inside the body of the magazine before the gun will cycle. Cases that are tarnished or bullets with too much lube are going to bind up ... even if the magazine is perfectly clean and friction proofed. A clean magazine will hold up until powder residue and wax builds up ... then you have to go through the above procedure again. Don't squirt oil in the magazine ... it may be a Band-Aid fix but the oil will soon draw powder residue and foul up again. Remember .... clean and dry!!! BX-25 problems? - Ruger Forum
