Like many I have some issues being under gassed on my MPX.  Since a suppressor will eventually be used I feel something like a Krink type booster would be of use.
I don't really want to use a thread adapter open up the port nor re-thread a barrel.  
 From HK parts they do have a 13.5 three lug adapter and also a flash can type of brake that can be bought separate . I can't tell if it is just a hollow can or if it has internals to increase the back pressure.
 Veriforce Pig.  Looks to be just a hollow tube so probably little to no back pressure on it

 That leave me using an adapter unless I am just not finding an alternative. Am I missing something ?