Is it illegal to hit a steel ball with a bow bought online?

Depending on the specific situation and location. In our country, it is not explicitly forbidden to hold compound bows, but it is also not allowed to be taken to public places, especially public transport. If you use bows and arrows for entertainment at home, it is not illegal as long as it does not hurt others. If you take the bow and arrow to public places, such as parks, schools and other places, it will violate the local public security management regulations and even constitute an illegal act.