I know they used to sell the whole gun in a kit that had both a 8 inch and 4 inch barrel that you could easily switch between. They now sell a newer version that comes with only a 6 inch barrel. I've only got the version with the 6 inch barrel. I'm not sure where you can order it from, but I do know the old kit allowed you to change the barrels by removing the barrel at the pivot screw. If they still sell the 8 inch barrel separately, it should be a real easy switch. You may even want to keep the old barrel handy if things don't work out with the SA6. Good luck bud,
Randy