something to note. the new old stock ones being sold on aust ebay at the moment (KF? stamped indian made clips) aren't as nicely stamped as the others i have (a mixture, mainly
Australian
made). the indian made clips take more work to get them to strip smoothly and even when finished still aren't as nice as the others.
with mine i round off the leading and trailing edges of all of the holes with a jewelers rat tail file. i bend the tabs straight and smooth off and round off the top edges. then bend the tabs open past straight. next i take a flat mill file and smooth the sides being careful not to hit the bottom with the corner of the file. the bottom, the inside of the channel and any coating left on the sides is smoothed with sandpaper. finally i bend the clips back in.
with all this done, a loose clip (held in your hand not in the charger bridge aka no magazine spring force), will strip with about 1/2 to 1/3 the pressure that an unmodified one needs. it takes me the better part of an hour each and it is probably way over the top but i can get a bit obsessive.
edit. nothing to do with the feeding issues, it just makes them smoother.