There is a simple test for lead softness, requires a known pure lead piece, make a fixture to hold the suspect lead, arrange a piece of wood hinged at one end with a sharp point on the bottom side at the end. place point on the pure piece .hang about 5 lbs of weight , note time done . then after a set time observe the point penetration into pure lead. then do it with a suspect piece, the depth of piercing compared to the first will give you a good idea of hardness. This is not very precise I admit . the addition of a calibrated guage would be more accurate. This was taught to me by Roy Keeler in the old days gone by. Really old Bob