You could create a CSS class for this and apply it to your columns. Since the gutter (spacing between columns) is controlled by padding in Bootstrap 3, adjust the padding accordingly:
.col {
padding-right:7px;
padding-left:7px;
}
Demo: http://bootply.com/93473
EDIT If you only want the spacing between columns you can select all cols except first and last like this..
.col:not(:first-child,:last-child) {
padding-right:7px;
padding-left:7px;
}
For Bootstrap 4 see: Remove gutter space for a specific div only