Some never tame down all the way, they just barely tolerate handling. I have a female pewter like this, she was very snappy and defensive from the first day we brought her home. Consistent, gentle, infrequent, and short handling sessions where she wasn't put away unless/until she wasn't snapping helped a lot, though when in-hand she never relaxes and her body is always very stiff, and she has improved to the point where you don't end up bleeding while cleaning out her tub.
That said, she just dropped good four eggs last Friday night/Saturday morning - her first clutch ever - and she started hissing as soon as the lights went on in the snake room and she really cut loose once her tub was opened up. Removing her from her eggs was an exercise in letting her wear herself out on a roll of paper towels while sneaking my hand around behind her to pick her up.
