Links to popular troubleshooting and tuning topics:
Barrel troubleshooting and accurizing for the DIYer (and an example)
Bore lapping versus polishing and fire lapping versus cast lap
Barrel crowning - brass screw method
Barrel machining
Barrel machining - reamer selection for leade
Adjusting a regulated PCP
Regulator creep, contributing factors, and how to deal with it
Regulator recovery time and related troubleshooting
Regulator pressure changing with the reservoir pressure
Barrel troubleshooting and accurizing for the DIYer (and an example)
Bore lapping versus polishing and fire lapping versus cast lap
Barrel crowning - brass screw method
Barrel machining
Barrel machining - reamer selection for leade
Adjusting a regulated PCP
Regulator creep, contributing factors, and how to deal with it
Regulator recovery time and related troubleshooting
Regulator pressure changing with the reservoir pressure