Sabotloader,
I have the gun that was supposedly made in Provo Utah.
That's what it says on the barrel.

I don't know where my gun fits into your thinking, but I
think it is still a pretty good gun. I only have one hammer.
The destruction manual calls it a "Universal" hammer. LOL.
I know what you mean about a "science" to getting the #11s
to go off reliably. I don't know about the stiffness of the
spring on the bolt I have. I don't have anything to compare
it to. It seems pretty stiff. I have taken the bolt down.