I did it to mine and I like it. I don't think it makes the receiver any weaker. It doesn't take that much of a beating anyway. Cleaning from the breech keeps the crown of the muzzle from being damaged and also keeps the chamber from getting the residue from the barrel pushed into it. If you use a Boresnake or Otis cleaning system it may be a moot point as you can clean from the breech with those anyway. As for why Ruger doesn't do it, probably a cost issue.