I just looked at the cannon-mania web site. If I am looking at the kit you are talking about it is .56 caliber, not .530 caliber. Are we talking about the same kit? The cannon-maina price for the one I am looking at is $186.95
I don't know if it is accidental or intentional, but on cannon-mania's it does not say the barrel is brass. it says the hardware is brass, but it does not talk a heck of a lot about the barrel. The enlarged view of the barrel shows something wierd in the area around the trunnions. That would be something to investigate before you plunk down your money.
If it is .56 caliber instead of .53, that would be fine. There are .535 molds readily available due to the T/C Renagade .56 cal smoothbore. Another nice thing about .56 is that it is also known as "28 gauge". That means that you can have alot of fun experimenting with the destructive powder of lead shot in 28 guage plastic wads, or simply load the shotwith 28 gauge over-powder and over-shot wads.
So, are we talking about the same kit?