Effective range of 300 feet? No. Half that at best. She was using number 7.5 and it was either a
300 is pushing it, but certainly more than half that. I can routinely hit birds at the clay course at 75 yards with a 20GA and a full choke shooting #7.5 or #8. I have friends (who are admittedly much better shooters than I) who can do it with a 28GA.