Lol. What? You know the amount of rounds needed to kill a barrel in a short space of time right? You think someone with a combat loadout of mags firing quickly in semi auto is going to do that? Looooooool.
I've mag dumped full auto firearms. Never once was I concerned with blowing up a receiver.
I think you've gotten hung up on "spam the trigger". Yes, if I'm on my own and I need to take out 5 other players in close proximity to each other that know my general location, I'm going to be pulling that trigger as fast as possible. I really don't know why you're taking an issue with this. I'm not sure what mentality of playing you're coming at this from. I only really play milsims where I'm limited to semi unless running a support gun. I guess if you're full autoing through ferns on a typical Sunday skirmish, you might not appreciate the need to be able to shoot quickly in semi.