You need can do it. Just not with a consumer level vibratory bowl. I have a 2hp 3 cubic foot tub type one that will. The one gentleman I deal with in Illinois uses a 3hp x 3 cubic foot bowl type and has good results. It has a built in seperator so it seperates 95% of the pins from the brass and they stay in the machine.
You are looking at about $4,000 for a new basic manual separation bowl tumbler with enough horsepower to drive the pins.