The interact key is overused for far too many actions in Payday 2 these days. One press of the F key can mark a special, yell at a cop, dominate a cop, tell a bot to drop a bag, tell a bot to come to you, yell a civilian, call a teammate to you, it's a mess. With this mod, you can handle one of those functions (marking specials) just by damaging them, which also skips the step of an additional button press. Some notes:

• The mod takes perks and skills into account when marking. So, with aced High Value Target, a bodyshot on a distant Sniper will mark him and cause subsequent hits to deal additional damage. Without that skill, he will be out of range, just like with normal marking.
  
• The mod will not mark an enemy who is already marked.
  
• The mod takes into consideration the interaction cooldown, meaning you can't shoot a million Shields and mark all of them.
  
• Damaging enemies with explosives will not work, since this would allow you to mark enemies from around corners and whom you otherwise wouldn't be able to see.
  
• If your attack will kill the special, it will not be marked.
  

Install the mod like any normal BLT mod.