Even if you would call the destructor, the object would still be there, just in a destroyed state. But you'd still have a variable referring to it. Also it would be undefined behavior for stack/automatic objects, their destructor is called at the end of their scope, so don't invoke it manually.
What you typically want to do for things like bullets is a STL container, almost always std::vector (see cppreference.com). You can dynamically add and remove objects, and iterate over all existing objects. So whenever someone shoots a bullet, you add it, and when it hits something, you remove it from the vector.
