whs,
I agree with the points you bring up about learning the call before season starts. And calling elk is very addictive!
Bugling Bull did sell the rights to the patent to Primos, and maintained the right to manufacture calls under the same patent.
One minor point of clarification, however, Bugling Bull actually does not use the same materials as Primos, and does not get their product from Primos. Different metal frames, tape, latex, manufacturing method, etc.
Thanks,
Corey