I have. Really helped Remington's lack luster lock time, but is prone to some other issues. Plus I've had an issue with the firing pin. Originals were made of titanium, and now think they are aluminum with a steel insert. There is at least one other company doing a speed lock kit, and I think I'd use their pin with a Holland spring. Or simply use the Holland spring. Still the kit seemed to help my off hand shooting accuracy.
gary