As far as high cap mags go, Google Lee Enfield mad minute, 15 rounds, aimed, 300 yds.,under one minute. Often exceeded, sometimes by as many as 25 rounds. 40 rounds aimed fire in a minute. This is with a bolt action rifle, so hi cap mags make not a bit of difference.
your right, high cap mags dont make a bit of difference.....if all you do is shoot at 300 yards and have plenty of time to practice shooting that well......
gee, i hope you never have to use a rifle in any other situation than the one you practiced countless hours in......