Yet 5.56 mm suppressors can be bought in real life -- Why not ARMA?

The TRG is my favourite gun implemented in the game so far, and after the chambering corrections we're no longer able to silence the gun, yet suppressors do exist for 5.56 mm guns in real life.
It would seem an odd choice not to add it into the game too, as the EBR is the only gun using a 7.76mm chamber, yet it has a suppressor available for it.
The 5.56mm chamber has (currently) 3 guns using it - SDAR (Not sure you'd be able to suppress that however), TRG-20 / 21, and TRG-21 EGLM.