G&P metal body on ECHO M16A4

Anyone installed one of these yet on their Echo M4/M16?

I'm having a heck of a time.

Summary of G&P MBK install problems.

SOLVED
1. Ejection port spring - must be tensioned when installed to work properly. Due to poor manual photos. SOLVED. NO MODS REQUIRED
2. Receiver terminating point for charging handle spring - small hole on inside of upper receiver. Screws in there. Due to poor manual photos. SOLVED. NO MODS REQUIRED
3. Outer barrel wouldn't fit into upper forward notch on body - widened notch on upper receiver using Dremel cut off wheel. SOLVED. DREMEL REQUIRED
4. Echo selector switch plastic insert too tight in G&P body - sanded around plastic backing piece. SOLVED. SANDING REQUIRED (makes piece nearly non-functional on original body). What brands have you used that work without modification?
5. Echo bolt catch does not fully seat into G&P body - Dremelled upper part of post that inserts into hole in metal body along its length. SOLVED. DREMEL REQUIRED (make piece loose on original body)

UNSOLVED
6. While boasting a functional ejection port cover (catch is spring loaded nicely, a great improvement over stock Echo), it won't close when GB installed. I've heard it's not designed to close. Is this correct? If so, why make the catch so nice?
7. Body pin above trigger won't align. Have heard GB may be hanging on charging handle. SUGGESTED SOLUTION: RUBBER MALLET. Haven't tried yet.
8. Can't align the front body pin holes. Have heard GB may be hanging on charging handle. SUGGESTED SOLUTION: RUBBER MALLET. Haven't tried yet.
9. Mags won't hold in place. SUGGESTED SOLUTION: THICK TAPE IN MAG WELL. Haven't tried yet.

IDEAS
- Buy G&P charging handle, mag release, and selector switch and hope these items fit better...maybe even a G&P gearbox shell.


Help.

Thanks.

John

After taking a break, I figured I'd try to get my G&P body on again.

Here are a couple pics showing where I'm stuck.

Stock Echo gearbox and body won't line up to drive the body pin above the trigger.

Something preventing top and bottom from meshing to drive the front pin. Gearbox is flush with bottom of lower receiver, so I don't think a wack with a mallet will work.

Looking at my stock Echo charging handle, it's grooved on the side that touched the gearbox. However, toward the end with the spring hook, the groove terminates and it's solid. Might this be the hang up?

http://www.airsoftforum.com/board/post-a2324-
http://www.airsoftforum.com/board/post-a2325-