My dad made a 3lb pot roast in a pressure cooker. He said he cooked it for 1 1/2 hours (seems to long for me). He checked after 50 minutes, it wasn't done, but had already shrunk, so he continued to cook it until it was tender. It was the size of a hamburger patty by the time it came out! It was tender, though. I don't cook many meats in pressure cookers. any ideas?