A couple of weeks ago, I smoked a 3 1/2 lb chuckie at 230* to and IT of about 160* and it was delicious. It was tender, juicy and very good to eat either as an entree or in sandwiches. Thinking how really good this was, I thought I would upgrade a little today. I smoked a 5 3/4 lb eye of round at 230* to and IT of 130*. It was beautiful inside but tough. I sliced it very thin and that helped a lot but still the toughness detracted from the overall enjoyment. Any thoughts as to why the eye of round was so different from the chuckie.