I've always had issues with MadBulls, with the exception if the tracer rounds. They don't feed well at all. Their polishing system seems inferior to Bastards and the BB's feel rough in comparison.
Oddly enough, I'm running the MadBull tightbores in all my AEG's yet the inner barrel is where there are jamming up most. Second is in the mags. The only way I managed to shoot through the bags I had was to put a few drops of silicone oil into the bags to 'slick' them up a bit. It's only a temporary fix as excess lube would need to be cleaned out of the hopup and inner barrel more often.
Now, the only things I allow MadBulls in are my 40mm's!
I'm wondering how many people without issues are running stock inner barrels vs. tightbores?