Consider me wooshed, then. 
Note: I’ve seen a .50 Barret fired from the shoulder before with no injury. Incidentally, I was about 10 feet away from the rifle, and the shockwave seemed to do more damage to my spine than the recoil did to his shoulder.
Although it’s definitely not something you could do regularly or accurately (weighing ~30 pounds), it’s possible to fire it from the shoulder without injury.
Not something I’m willing to try.
The muzzle brake is extremely efficient on the m82a1. It’s said to be only slightly more than 12 gauge magnum loads.
Which is still a HUGE amount of recoil, but it won’t break your collar bone if you’re competant.