The .223 WSSM has just about exactly the same powder capacity as the .22/6mm, and I've used .223 WSSM data in a .22/6mm with just about identical results, though obviously that would depend on the throat length in the .22/6mm, plus throat wear in either rifle. But the main point is that .223 WSSM data is a good starting point for the .22/6mm AI.
