Team Logo. The Houston Colt .45s were a team in Major League Baseball. They played in the National League. In 1965, they moved into the Astrodome and became known as the Houston Astros. Retrieved from "https://prosportsteams.fandom.com/wiki/Houston_Colt_.45s?oldid=14687" Categories: Former MLB teams Teams in Texas Add category Cancel Save Community content is available under CC-BY-SA unless otherwise noted.