It was Smokey Hale that introduced me to smoked bologna in a recipe from The Great American Barbecue & Grilling Manual. As I recall, Smokey used a basting sauce with garlic as the predominate seasoning, but it had onion powder and celery seed as well as a few other things, this is an excellent combination of flavors. Over the years I've seen so many different ways to season and smoke bologna, it's impossible to list them all here.
In the city of Bologna, Italy where bologna originated it is lightly smoked, but from what I gather it was barbecuists in the USA that were the ones to perfect smoking bologna using the BBQ flavors we all enjoy. Because of this smoked bologna goes by names like "Oklahoma Prime Rib, or in Tennessee it's known as "redneck round steak". On many of the BBQ and smoking forums folks use a variety of methods from no seasonings, brown sugar only, pepper & brown sugar, mustard slathers, to basting or spraying. The best tip here is: if you use a rub, be careful as bologna is high in salt already... so use a low-salt or no-salt rub.
In this method below I'm using my garlic pepper blend (see the Rub page for the recipe), and a low salt rub that is slightly sweet. And I'm using a slather with yellow mustard and Worcestershire (start with 3 or 4 tablespoons of mustard and add Wooster to thin it out). The mustard delivers a vinegar flavor and is an anchor for the rubs. The Wooster is good on most all cuts of beef and helps to accent the other flavors because it contains anchovies, giving food umami (a savory flavor).
Most techniques are similar and mine is no exception. First I remove the outer wrap and the red skin from a chub of bologna, this chub is 2.5 pounds.
Step 2 is to cross score both ends and the sides, then apply some rub and the mustard slather. Plus a light spray of oil to discourage sticking on the grate.
Step 3 is to smoke it. With a chub of this diameter and thickness, my smoking time was close to 3-1/2 hours using an indirect set-up and pit temps in the 225° to 250° range. Remember, bologna is already cooked, so you are just heating it up to get a crusty bark and to develop some good color. You want the score marks to open up. I did not spray this one while smoking, but I generally mix a 50:50 solution of Wooster and water and have it on hand just in case the bologna looks a little dry, just spray them once or twice if needed.
Step 4 - At this point you can slice it and make sandwiches, or little sliders. It can be cubed and served on toothpicks. Or it can be rested and then cooled to slice later for sandwiches (a quick pan fry with some butter will wake-up the smokey flavor). For this cook however, I did kind of a burnt end finish. After cubing it, I slightly re-seasoned it and returned it to the pit for 30 to 40 minutes (just keep your eye on it so it doesn't dry out), then I sauced it and glazed it for 15 minutes or so.