1. Make sure magazine is unloaded.
2. Remove internal components.
3. Remove replaceable feedlips.
4. Try to fit a .22LR cartridge through the slot in the top of the magazine body. It will drag slightly at the front and the rear of the shell.
5. Use a small file or hobby knife to gently scrape a very tiny amount of material from both sides of the opening.
6. Test that the cartridge now slips through with no resistance whatsoever. If it still makes contact, repeat #5.
7. Reassemble magazine making sure the top of the spring has the last coil towards the front of the magazine.
8. Magazine will now function perfectly.