I can kinda see where the rounds are rubbing the feed ramp. Will try some serious cleaning and see if it will polish up. Not 100% certain but I think it is related to this mag. I set it aside and used another one for the rest of the day w/o the same issues.
Maybe it’s not tensioned correctly? Try doing that (again). You might not have got it right the first time. They can be tricky. It’s the only thing I can think of. Unless there is a build up of gunk that the picture doesn’t show.
Over tensioning after a mag rebuild will cause rounds to hang.
After rebuilding a BX-1, fully load then push each round out with a chop or skewer stick to check for smooth feeding and loosen the tension screw just enough for proper feeding if rounds don’t feed smooth.
Too loose will cause another issue.
Since yours is rebuilt, try the test and loosen a little at a time until it feeds smooth.
An “exact-edge” aftermarket extractor is preferred for replacing the Ruger stamped extractor after 1-1,500 rounds or so.
Also try a barrel “chamber check” to see if rounds drop in and fall out easily…if not spend a little extra time brushing it out with solvent.
Had failure to extract and also round half way out of chamber after firing. Found crud buildup under extractor lip. Would not totally engage rim of cartridge. Took piece of dental floss and made a loop and ran it back and forth under extractor lip. Cleaned up and solved problem.
Inside of mag varies from “kinda gritty” to “mostly ok” and the followers about the same. Some variation due to differing numbers of rounds and brands of ammo run. Not that many rounds - if less than 100 is “not many.” These mags got fed Rem TB’s, CCI SV, S&B Club, Aguila, Tac 22 in no particular order and w/o cleaning between brands.