How powerfull is the 10 bore DR??
VERY

Can this one be loaded with Light smokeless loads??
Probably Nitro for Black / Light Nitro

"is there anyone still makes up 10 gauge brass ?"
10 Gauge Shotgun Shells are available
10 Gauge Brass - not sure

Bore guns are easy to get to shoot.

Barrels are almost always thick and strong.

Price is good.