Hi Jim, Actually I should have reworded it I guess. I didn't mean to test to failure, but maybe a margin for user error or torque wrench inaccuracies perhaps 20% over? What i don't understand is if the insert is flush with the surface and bottoming on the barrel or gasket why would it strip the thread in the head? Aren't the heads even strong enough to compress the gasket without fear of failure of the inserts (outer) threads? Cheers, cliffa.