RE: Pyrodex Powder Life Expectancy
Only the gun range know for sure. Assuming your rifle is already sighted-in with another powder, the main thing you want to look for is consistency. If you can shoot 3-5 shot groups with it... it's fine as long as you are not dialing a million scope clicks so shots move upwards. If you normally shoot a similar strength powder & this one falls two feet lower at 50 yards,dispose of it properly.