What Huglu/CZmodels are you talking about with aluminum receiver?
I cannot remember, i only handled the thing briefly and had very little interest in it. The turkish guns don't have much of a following or reputation here, rough shooters use baikals as they are built like a tank and are cheap and plentiful. In addition the last time i perused the shotgun shelf in the local dealers, i could buy an english sxs boxlock for less or a used beretta 682 or browning 325 for the same money as a new turkish gun.