So I'm looking into getting either the M93R or the MP9, as a secondary weapon. The M93R is bad ass, I love three shot burst guns. The MP9 is bad ass too, and It will look amazing with Action MPX silencer.
Are there any upgrades for either of the two? Is there an inner barrel that will fit the MP9 with the 200mm? Are GBB compatible with AEG barrels? I'd like to put a 300mm in there.