Building a $1200 RCA Interconnect Cable

Last week I set out to build a $1200 RCA Interconnect cable using:
- WBT RCA (Copper) connectors
- Silver solder
- Solid core wire
- Shielded cable
- nylon cover
And of course the regular tools to get the job done.

As I was soldering the braid to the body of the connoctor, I noticed that it took forever for the solder to stick to the metal body; so I turned up the temperature on the solder station from 750 degrees F to 800 dagrees F. But it still took long to make the solder connection. I started to wonder why. The WBT connectors were advertised as copper connectors; and I know that scopper is soft and only second to silver in conductivity. I then took a knife and started to cut away at the body of the connector to see how hard it was. It was like cutting into steel, very hard. This is definately not copper. I then took the knife and cut away at the center pin in the connector, and sure enough that bit was much softer and easier to cut into, and also heated up quickly for soldering. I then went and got an expensive $1500 pair of cables with WBT RCA connectors and perform the same test. To my surprise it was the same result: it too had only the center pin made of a soft metal (copper I hope).

When I read description that say that the connectors are made of 100% copper, I take it to mean that the whole connector is made of copper not just the center pin. The question is: 
Is this a scam or is it common Industry Practice to use brass or other metal for the body of the RCA and other connectors and only use copper for the center pin? 

What are you thoughts.....???