This issue is much worse when you are prone and a dropped weapon is between you and the body. It's very difficult to collect the magazines from the body unless you crawl right up to (more or less 'inside') the body, or move around the dropped weapon to approach the body from a different angle so it's not obstructing your 'line of sight' to the body.
This means you potentially have to break from your cover in order to get around the other side of the body to collect the magazines.