My 410 Allen Magnum will come very close to matching this, if not matching it exactly. Just got my reamers in and test barrels so testing will start soon. Judging from the 375 AM driving the 350 gr SMK to 3250 fps easily, I would be very suprised if the 410 will not get 3200 fps easily with a 395 gr class bullet and do so in a rifle that would be dramatically smaller then what the Barrett requires.
The Barrett is just to large in case capacity for what needs be for this level of performance.
Its an interesting round and it was a way for Ronny Barrett to stick it to California when they banned the 50 BMGs but there are more efficent ways to get this level of performance. Cleaner burning, longer barrel life and better consistancy, all around better ways to get this performance.