This information is paraphrased from John Taffins book Big Bore Sixguns pp. 100-103. Anyone interested in big sixguns should find a copy of Johns books.
Freedom Arms Model 83s were designed by Dick Casull for the 454 Casull cartridge. Dicks favorite make of gun and the guns used for most of his 45 Magunum development was Colt Single Actions. By comparing Colt Single Actions and the FA 83 you can see many similarities which also reflects his soft spot for Colts.
The grip of the 83 is not a traditional style single action grip. The grip is much straighter than the grips found on either Colt Single Actions or Ruger Super Blackhawks. The grip was designed more straight to prevent the gun from rolling too much, possibly out of the hands, when using heavier loads.
John also says this grip design is an achievement in human engineering due to making the 454 manageable to shoot.
Take Care,
Scott
