I love my rockets!! ecspecially the sidewinders, BUT the ultimate steels will only screw into certain inserts more than one thread. I am not sure why. They only catch whith 1 thread on, I think it is the gold tips and one other. I had a customer return them because he was not comfortable with them not being very secure. When I contacted Rocket they were aware of the problem but, at that time , were not in the prcoess of changing anything.