I like the high poly minus the gummy parts that you have floating on the sides, Also it looks like your bake is inverted and seems to have lost a lot of the detail around the barrel and the front sight... Did you do an AO bake along with the normal bake? If not I suggest doing that as it will help the normals pop more.
Thanks for the replies. I think I've figured out the problem. I'm not that great at making a good low poly and this resulted in the cage being just right in some areas but way off on other areas, especially at points where I've used floating geometry. I'll run it through xNormal and see how it turns out using the settings…