- Iron sights. The TRG had its sights remodelled after feedback that they were hard to use/ugly. I would suggest a similar improvement for the Mk20.
- Fire selector. There is a separate ticket for this already by the_killer23:
http://feedback.arma3.com/view.php?id=11464
His description :
"The current Mk20 armpit fire selector is incorrect and modeled off the JLS airsoft replica. The fire selector should be a rotary dial located under the trigger (modeled as a flat grey piece in-game)."