Oh man, your comment made me remember my first game that was just like tank wars. I always called it banana wars because you were 2 apes that threw bananas at each other.
Just found it.... "QBasic - gorrilas" https://www.retrogames.cz/play_654-DOS.php. So many memories playing this against my dad, punching a hole straight through some buildings at high velocity because he could never figure out how to do adjust his angle and velocity to account for the shifting wind speeds.
Colt makes AR15s. They held the original patent until it expired in the '70s, and then everyone else started making it too.