I store my powder in wooden boxes marked explosives. This way if my house catches fire and the fire department enters my garage, they see them and they can remove them. A wooden powder box will not build dangerous levels of pressure like a sealed metal container in a fire, the wood box will vent and burn long before that happens. A simple latch locks the box to keep kids out.
It seems to be rocket science to other people to figure something to lock their powder in...
