[Bellerophon]

I just finished rewiring my CA MP5SD with 16AWG wire + deans, as well as installing a 3/16" sorbo pad and the requisite grinding and sanding of the piston teeth to correct the AOE. I'm extremely impressed by the improvement in responsiveness and rate of fire, especially considering everything else including the battery (8.4V NiMH mini type) is stock. However, in doing these upgrades myself, I've encountered some problems:

I. FPS loss, was shooting 320 ± 5 before and now shooting 260 ± 10. I expected some FPS loss when installing the sorbo pad due to the reduced cylinder volume, but not this much. I'm already testing various parts for compression as per Thundercactus' thread. I suspect the cylinder's side vent is now too far forward.

II. Tappet/nozzle in 'open bolt' position, sitting fully rearward at the beginning and end of the shot, moving forward with each cycle of the gearbox. The tappet plate isn't apparently stuck against anything, moving freely back and forth at a finger press when the shot is paused in forward position. The tappet and nozzle still seem firmly attached to each other. Also, when I was working inside the gearbox, I noticed the sector gear has only a little round post to draw back the tappet plate with, in all other gearboxes I've opened there is a little cam on the sector that engages the tappet, is this normal?

III. Short trigger pulls on semi will produce a burst of full auto, which ends once the trigger is pulled fully to the rear. I'm pretty sure I reinstalled the contacts correctly when I was finished soldering, but it seems like there is some pre-engagement going on here. Resolved, thanks pestobanana!

IV. Probably related to both II and III, misfeeds and double feeds.

If I can combine the power and reliability I had before with the responsiveness and quietness I have now, I think I'll be having a very fun summer. Thanks for reading this far.