Add all ingredients to a large crock pot and cook on low for 7-8 hours or high for 5-6 hours. If my roast is very thick sometimes I will cut it into 2 or 3 large chunks. You can either take the time to remove the stems from the pepperoncinis before adding them to the recipe, or remove them after it is done cooking. I find it easier to do after cooking. They slide right out of the pepper. My family likes lots of peppers, so sometimes I use 2 large jars!
When the meat is done and the peppers are soft, take the meat out of the pot onto a large platter and shred the meat, removing any large pieces of fat. Return to the crock pot and heat for just 15-20 min. more. Butter the hard crusty rolls, pile it high with the meat and peppers and take a big bite! Delicious! (the butter helps mellow out the spice-it is a litte spicy! also, soft rolls will not work- they absorb too much liquid and turn to mush and fall apart)