Tom,
From what i have been told it was mostly designed to snub the California 50BMG ban. The case is a std 50 Cal BMG that has been shortened to about 3.250" long, necked down to take the lathe turned .416 projectiles. It burns 200grns of powder, pushing the 400grn bullet 3300fps. Cases are expensive, as are the primers. There are no good long range 416 bullets available at this time.
There are much better builds out there, in my opinon. You can get the same or better performance out of the 408 C-T wildcats, 338,375,416 or even larger cals. You have a cheaper cases, production run bullets, use less expensive actions and even have the capability to build carry rifles. The new 375 chey-tac coming out soon will equal or better the balistics of the 416 barrett.
Dave