Thought I would give an update to anyone interested
Ended up giving up trying to get the pellet liner to shoot slugs
Machined down a 700mm slug liner to fit , fitted a slightly heavier hammer weight
Running h&n 25g and 30g 218s at 960 ish with good accuracy and getting around 70 shots per fill
The pop you get with starlings is amazing :D
Can lower the power wheel and run 16g pellets without changing zero
