The shells were on!  [:(]  I just think I left the shrimp in the smoker too long…  Bummer

 
Yeah, that could happen too. I did 20-25 minutes on the U12 size. The 15-25 I think I did closer to 20. I also ran the cooker at a lower heat—-once I got the smoke puff and closed it I turned the heat down a touch to medium-low.