National Fire Protection Association
Rod is correct here, and to add:
There's a difference between shipping and storing powder. Shipping comes under DOT regulations and storing is controlled by local jurisdictions. Most jurisdictions adopt the NFPA standards. NFPA changed a little while ago (2010). Check with your local jurisdiction (typically the Fire Marshall).
2013 NFPA (actual chapter is 495) allows residential storage for personal use of:
20-Pounds of Smokeless propellants may be kept if in the original containers. This may be increased to 50-pounds if the containers are stored in 1-inch (nominal) thick wood boxes or cabinets.
Now the NFPA itself is not law but it is the recommended code and like building codes has been adopted by most cities counties etc. that have the authority to adopt such codes, note they may use an older code and a few years ago the storage limit was lower.
If you are storing over 50 pounds of smokeless powder in a wooden storage container (magazine, yes that's what the box is called), or 20 pounds in the containers it came in; you are most likely breaking a local fire ordinance. Doing a quick look at state law, which itself does not contain anything directly about this, it would appear that the city/county ordinance would be required to have a punishment similar to a Class III Misdemeanor (three months in jail and or a $500 fine, maximum) .
