It seems that the manufacturers were somewhat concerned about the effect of water exposure on their early steel loads. I mention this because I recall that Remington went to great lengths to market the water proofing on their old line of steel duplex loads, the ones that came in the cool olive drab plastic with black bases. Those were great shells for their time, and I bought a mess of them on closeout. Still shooting them through my beater 870 and my old Citori, in BBx1 and BBx2. Have a few boxes of 2x6 for pheasants in non-tox areas.