The class pull-right is still there in Bootstrap 3
See the ‘helper classes’ here
pull-right is defined by
.pull-right {
float: right !important;
}
without more info on styles and content, it’s difficult to say.
It definitely pulls right in this JSBIN
when the page is wider than 990px – which is when the col-md styling kicks in,
Bootstrap 3 being mobile first and all.
Bootstrap 4
Note that for Bootstrap 4 .pull-right has been replaced with .float-right
https://www.geeksforgeeks.org/pull-left-and-pull-right-classes-in-bootstrap-4/#:~:text=pull%2Dright%20classes%20have%20been,based%20on%20the%20Bootstrap%20Grid.