I don't think you NEED a second cylinder to fire the 45 lc or 480 ruger from your guns. I shoot mostly 45 LC from my Model 83 454 and sometimes factory 480 Ruger ammo threw my 475 Linebaugh. I could see where you could have cases stick or worst, pressure spikes when shooting Casulls threw a crudy chamber. But shouldn't be a problem if you clean your cylinder between cartridges. Im guessing Freedom arms is just being precautious because the 454 Casull's high operating pressures and not wanting customers complaining about stuck cases.
Plus they want to sell you an extra cylinder for $400. If they didn't they would offer the 83 in 45 LC & 45 ACP since they all ready are set-up to chamber these rounds in the 83. Yep, there in buisness to make money. Just like the way sell you a $2500 gun then charge you an EXTRA $100 to reduce the trigger to 3 lbs from 4.5lbs, or MORE cash for action tune, ... wouldn't you think these would be "standard features" on a gun that leaves the factory as a "Premier Grade"?
I love my Freedom Arms, but they sure make you pay to play.