Youd probably melt the barrel trying to sustain that for a minute.
M16A1 rifles and most M4 carbines in my experience more generally burn a hole through the stainless steel gas tube before the barrels will melt. It helps some that there's a second or two of intermission every 30 rounds or so, except that there are beta-C hundred-round magazines and even a 225-round *M-SAW* magazine on the market now.
But if youy just dump magazines as quickly as possible, on semi or full, somewhere around Number Fifteen to Number Twenty things will most usually come to a halt.
That's when it's time to pick up another rifle. And, of course, more ammo.
There's a youtube upthread showing just that. The handguard is burning like a kerosene lantern, and the rifle suddenly becomes a single shot ....