I don't know about the reproductions but I had an orginal one with a pistol when I was living overseas. The US has relatively conservative gun laws, you know. Anyhow, as far as using it as a shoulder stock, I was mightily unimpressed with mine. The problem was that the fit was poor, resulting in a wobble. While it probably helped some with shooting at longer ranges, not that I had that opportunity, a tight fit would have been better.
On the other hand, what I had must have been at least fifty years old and I'm not as tight as I used to be either.
Shoot low, sheriff. They're riding Shetlands!
Underneath the starry flag, civilize 'em with a Krag,
and return us to our own beloved homes!
Buy War Bonds.