There are some folks in our part of the world that have Plotts that they coon hunt with. I honestly believe that he is part Plott. The girl I got him from swore to me that his mother was a Jack Russell. Possibly he might be half Jack Russell and half Plott and he got his color from the Plott. I would just like to now how stinking big he is going to get. He is a very intelligent and very active little dog. For a puppy though he is very easy to handle.
Based on what you said:
5 months, 27lbs
I think that dog will fill out to 40-50 lbs.
No bigger than 60lbs
Take a picture of him with his feet and his body, so we can see how big his feet are.
This "Jack russell"may have a cross.
If you think it's smart and well mannered you should hold on to it and train/teach it.....good dogs can be hard to find.
My friend has a plott hound and it's dumb as a box of rocks, always was and always will be.