This Machine is great for mid to close-ish range, imo. It's the one I tend to use for firing from the hip as well as casual mid-range sniping. I use it a lot against cazzies or Fiends or Legion, for example. It has a pretty big spread, however, so it's not going to be your long-range 'go to' sniping rifle. The Hunting Rifle (or Sniper Rifle or Gobi or...) would be the more efficient for that purpose.
This is really the answer. Guns like the Trail Carbine and This Machine and other GP Rifles are best for Medium Range work, where the Hunting/Sniper rifles are best for long range work. The Marksman Carbine seems to be the best bridge weapon, for me, between Long and Medium Range.
However for a Medium Range weapon, I prefer ones that use Clips as they reload faster.