(You know this but...) The main way to go about modeling is called Sub Division modeling. What this is essentially is the addition of supporting edges to your low poly and then Smooth the mesh adding sub divisions, or Turbo smooth in max. So I say this, because if you have your "Mid Poly" (just the mesh after the low poly…
Okay, upon your request, I shall binge watch Millenia videos. ;) AND hopefully take part in his gun tutorial series. With Millenia, and with a lot of other advanced 3ds Max users, they use a max plugin called TexTools. It increases your capabilities and convenience when UV mapping and texturing. I think I'll get that.…