CA M15 hop up issue

[mr.hyde]

lets start with the details...

Classic Army
M15a4 sportline
CA metal hop up and rubber
gun doc built gear box
380 fps on .25g
6.03 tightbore

1. I'm having a bit of an issue with an scs concave hop up spacer I recently bought, it seems i have little to no hop up. When shoot I get maybe 20-30 ft of range then drops could this be a compatibility issue. Worked fine prior to change. Will hopefully get around to a chrono/ just swapping hop up spacers back.

2. I am looking at metal bodies at the moment and was wondering how compatible G&p metal bodies are with ca parts. Also will this improve how well my mags feed if a snugger fit? I am currently using the velcro trick and mag brand mags.

3. My KWA mp9 has some wear and tear on the feed lip inside the gun (not sure of the proper name, part number 18) does anyone know the cause or solution is to this problem?