I am trying to figure whats worth keeping and what to pass along. I have no history on these rifles and know little about them. I have been looking on line and there are so many different makers and different uppers and so forth. The black one is 556 with a mag tactical lower MG-G4 the hand guard is Midwest industries with a palmetto barrel . the lower one is 5.45X39 with a YHM receiver . Are there a big difference in the receivers value or quality? Thanks

[Imgur](http://i.imgur.com/gREZ50x.jpg)