DODS/Rocket targets
This tutorial will show you how to make a wall that can only be destroyed by rockets or grenade.
Make your Brush
Create the brush you would like to have remain after the wall is destroyed.
Now create the center piece of this. You need to give it a visual aspect that will let players know that it can be destroyed. You can use a similar technique to the DoD 1.3 maps, with 3 cracks in a "Y" Shape, Though you can use whatever you please.
Configuring the entity
Select all the parts of the wall that will be destroyed, and press the Tie To Entity button (Ctrl + T). Set the entity as a func_breakable and set it up however you wish. The only keyvalues you need to worry about are the Strength and Min Damage to Hurt. Since the Kar98 and Springfield snipers both do 120 damage, you need to set the Min Damage to Hurt to more than that. Rockets generally do 125 damage, so set Min Damage to Hurt to 125. The strength can be whatever you want it to be. I normally set it to 100 times the number of rocket to kill.
Test it out
Now you can test it out. Rockets may sometimes not do enough damage, thus not breaking the wall. Only rockets or grenades will destroy it.