Corrosive. Treat it all as if it was, even non-corrosive. My cleaning process is the same regardless of the ammunition and I've not had trouble. I've had bores eaten by "non-corrosive" ammunition. I keep a little USGI squeeze bottle of ballistol in my Otis kit and when I can, after I shoot I pull a wet ballistol patch or two through my bores right after shooting, while the bores are still hot. I clean again when I get home. I check the bore and pull a patch through on day 2 and check on day 3. I live in a humid environment. My shooter bores are mint, mirrors, so they clean easier. A pitted bore, even micro pitted, is like eating with cavities in teeth.