I havent done a deer roast but I have been doing deer stew with the meat cut into 1" - 1.5" chunks. It is outstanding. more tender than in a crock pot. I have noticed that it takes a lot more seasoning in an electric pressure cooker though. I'm fixing to cut my neck roast into 2" thick slices and do one in my insta-pot. I'm sure it will be great. I did a rack of ribs and I couldnt get the ribs out without the meat falling off.