I'm sure more technical explanation will follow shortly if not already, but it basically modifies your SBH/BH/old Vaquero to be (able to be) "freely spun" around to directly align each chamber for loading a round/ejecting a spent case. The stock set up will over-travel to its stop if you're not careful, requiring you to go around again for that chamber. The "free" part of the free spin is that there asre no stops at all (when being rotated for loading)...thus you still have to be the one to stop it,...but it also will spin in both directions without interference if you go past your intended chamber. All the New Vaqueros, and same frame (midframe) Flattops have a pawl set up which stops the chamber directly in line with the loading port, no over-travel.
The other advantage of the free spin cyl pawl in my experience is the ability to reverse the cylinder to retrieve a cartridge case with a blown out primer that binds up the cylinder and won't allow it to advance to the loading gate for removal. Also if you have a cartridge for example with a high primer that won't advance but the cylinder is rotated past the 'click' of the cyl pawl you can just turn it back and unload it w/o having to pull the cylinder.
I like it in my new and old model guns even better than the new vaqueros and flat tops that have the chamber alignment pawl. But since they already have a free spin cyl pawl, you can just unscrew the alighnment pawl and have the cylinder rotate both ways.
Add to that,if a bullet jumps crimp,the gun is out of commission.With the free spin pawl,you can reverse the cylinder,remove it and you are back in the game.
When hunting you may fire a shot,cock again,let down and then you have an empty chamber in there.With the free wheeled gun,I open it up,replace the empty quickly before following up on game.All my hunting single actions are free wheeled.
As an Amazon Associate we earn from qualifying purchases. Product prices and availability are accurate as of the date/time indicated and are subject to change.