Jmason,
I have not shot any so I can not comment.
Again, the beauty of the AR-50 is that its a conventional bolt action design. VERY LARGE, but conventional in every way. No different at all in barrel fit then a Rem 700. As such, the receivers are pretty easy to accurize and its very simple to install a match grade barrel. The factory barrels shoot pretty well with good ammo and with match handloads generally will do 3/4 moa.
That said, I have shipped of alot of AR-50s that I have rebuilt chambered in my 510 Allen Magnum and after accurizing the receiver and installing a match barrel, they REALLY shoot and they are easy to shoot.
My current 510 AM is on the AR-50 platform. I ordered a stainless fluted Navy Sporter contour from Lilja with 33" finish length so its a couple inches longer then the factory barrel but about 2 lbs lighter. Most would think this would increase recoil but that is not how a muzzle brake works. The less momentum a rifle has when influenced by recoil energy, the more effective the muzzle brake is at slowing the rearward movement of the rifle so felt recoil is often noticably less.
Now that said, a 750 gr A-Max at 2975 fps with 260 grains of H-50BMG is not a puff-puff load but its completely managable.
As to the comment about the Barrett82. I fully agree, they are fun as hell, but consider that the world record 1000 yard group with the Barrett is barely 1 moa compared to the world record heavy bolt rifle that is in the upper .1 moa range.
Also, for the cost of a Barrett 82 ready to shoot, you could easily have two AR-50s scoped up ready to shoot!!! Or, an AR-50 with enough ammo for many years of serious shooting!!!
The Barrett is a fine weapon but its not designed for extreme precision. You can get much finer accuracy and consistancy with much less investment.