I just started using the M27, and after throwing the fore grip and fast mag on it, I'm pretty pleased. It definitely turns into a killing machine... Once I get FMJ's I'll probably ditch the fast mag, but I'll end up using primary gunfighter when I get extended mag so I can use all 3. I'm shying away from any optics... for some reason I tend to ball out with iron sights in Treyarch CODs. I hate being EMP grenaded and the dot goes down on my sight.
FYI, like I texted you yesterday the heat maps are in Elite, but I think the webpage elite is the best. I havent really checked the console app, but the webpage lets you view a animated layout of the map as you're kills progress during the match. Just go to a recent match and hit "View Heat Map"
Here are some of mine: Aftermath
Plaza
Raid