My guess is it is non-canister grade powder and/or mil-surplus. Companies such as Wideners often sell such powders with data or recommended similar powder data.
You might try contacting some retailers to see if they have info. In the end, it will most likely be more trouble than it is worth.
I believe that might be Winchester-Western powder. They used to indentify there powders by number and may still do this. I looked in a 1977 revised loading data book and did not see this number in there, not in the shotgun or centerfire shells. Back then the shotgun powders where 452AA & 473AA (12 ga.).
452AA started out as a 12ga shotshell powder, but found a following with the early ipsc crowd in 45acp. Some of my Winchester data books list several 452AA handgun loads along with shotshell loads. It has long been out of production. It was replaced by WST, but they are NOT the same powder. For shotshells, there are many better powders out now, especially with the current craze of "clean" powders, and 452AA is in no way a clean burning powder. It is reverse temperature sensitive in that velocity tends to decrease with an increase in ambient temperature. If you like to shoot bowling pins with a .45, you'll love it.