Basically halfway through a range session some fine afghanistan moon dust, just a sprinkling, got inside the upper of my C7. This put juuust enough friction against the side of the BCG that it would not fully strip the first round off the mag. Immediate action, strip the mag, ditch the top round, re-insert, rack - same problem. I can't do this all day. Tried the scallop - didn't budge. I could see there was no chamber obstruction, so I reluctantly tried the FA and it sent the bolt home right away. Second round needed a tap too, but after that it was fine.
I was one of those convinced the FA was useless until I was presented with a use case in person. Glad it happened then rather than a more urgent time.
