The believed shelf-lifetime of Vihtavuori gunpowders is no less than 10 years, if saved and sealed in its first containers in a temperature circa twenty°C and relative humidity of circa 55 %. All Vihtavuori reloading powders are packed into bottles and canisters and further in fiberboard boxes. NRA High Electrical https://flockarms.com/product/vihtavuori-n340-powder-4-lb/