I looked it up, the Bersa made 1911 all appear to be made with stainless steel slides and receivers, many being Cerakoted to give them color. Tisas are carbon steel that is either Cerakoted or plated. Stainless is harder to machine, but is more corrosion resistant than carbon steel, so there is a market and most new stainless 1911's carry a price tag of around $900 or more these days.