All alloys aren't created equal. 
A cartridge brass of about 70/30 is described as excellent cold working
properties. And it is able to be reduced in cross section by more than 50%
without a problem before the need to anneal. Leaded brasses, often called free
machining or extruded brasses are described as poor cold working properties.
So.... use the excellent one and avoid the poor one.
Working in alloys with excellent cold working properties is an absolute joy.