Fry the diced bacon until slightly crisp, pour out bacon and grease and set aside until later.
Fry the sausage in the same dutch oven until browned, adding a little of the pepper to the sausage as it cooks.
Add the bacon grease and 1/4th of the bacon to the cooked sausage. Cook on low and add the butter until melted. Add the flour and season salt. Cook for 3 minutes to get rid of the flour taste. Stirring constantly.
Heat to medium, slowly add the milk, only enough at a time so it doesn't get too runny. Add the rest of the bacon.
Add the salt and pepper for your taste. I believe the more pepper the better. The longer this simmers the more flavor it has. This is great with biscuits, hashbrowns or chicken fried steak.
I always divide the gravy into plastic bowls enough for 1 meal and freeze for another day.