Steel cartridge cases are stronger and harder than brass, which unquestionably causes more ware and potentially more risk of damage to firearm's parts. This may -- or may not -- be consequential; for example, some Soviet block small arms were/are designed for steel casings, which obviously suggests they are better able to withstand these additional physical loads without damage. However, I would NEVER risk the long- or short-term reliability or durability of an expensive, high quality firearms for the slight incremental cost savings provided by steel cased ammunition.