Its correct enough for me!
When I open the case or pull it out of it's holster, its a "Colt 1851", a clone perhaps, but thats what it is for me. I am not trying to display it as an original or an exact replica of an original. It isn't going into a museum display to be peered at or have it's dimensions checked for historical research......its going to be holstered, and shot, and utilized for annihilating thousands of percussion caps, consuming pounds of powder and peppering many large pieces of paper or steel!
It cost me a lot less than any other 1851 correct caliber or not!
Its the same caliber as my 1858 Remington meaning I only have to stock one size ball.
If I ever get the urge to be historically correct, I'll buy a real one.
In my opinion Colt should have made the 1851 in .44.