Yeh Phil is right. Roller should not touch. If it does then that's a source of inconsistency right there.
It won't be hammer. The steyrs problems are wear, sealing and tolerances. Remove the stabiliser to test as well. That's also influenced by the weak chassis.
They're designed to be made easily. Not necessarily well.
If you want it to feel faster then shim the return valve. Leave the rest alone, even reg pressure. If you up the reg pressure you will most likely move away from its point of consistency as it won't be shimmed for higher pressure and all that will mean is more creep and a bigger change at lower pressure. The by product of turning the screw is to change the pressure but that's not what its prime effect is. The reg needs to be shimmed for higher pressures but you need to find its unique default pressure. You won't find it on an analogue gauge either.
The problem with steyrs is that every time they are stripped you disturb a number of things that can cause inconsistency. If everyone is not checked on assembly you are wasting your time or getting lucky.
Don't look for the high fruit, pick the low hanging stuff. It's extremely likely the issues you are seeing are the normal gun issues.
BFTA/NSRA County Coach
CSFTA Chairman/BFTA Rep