Here is my answer to a post on how to create resettable explosions. The block is a button_target. When you shoot it, it triggers an invisible button that calls a multimanager. The multi manager triggers an env_explosion and an ambient generic. I got a little fancy and put in some trigger_changetargets that cause the button to trigger a different multimanager each time so the explosions wouldn't always be in the same place.
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nevermind...