Though I undersand your liking for low poly work, I still recommend, like Lemonade, that you use more polygons, at least where it counts. For example, the magazine for the third gun in your pictures. I'm not saying to add so many polies that it's perfectly smooth, I'm just saying to add a few more, like making the base circle be something like twelve or fifteen sided rather than eight, because the magazine is a pretty large, round object in comparison with other smaller tubes (where you could get away with something like a three sided triangle for the base of a cylinder for something small, such as a wire). Besides, in modern day games, if you pay enough attention, you notice that many things are pretty low poly, they just have really good textures and normal maps that completely hide this effect. Good luck with other work