I have been monitoring several sites for smokeless powder and primers. I have ordered and received powder. No primers yet. You have to watch them regularly and be ready to act. You will pay a Hazmat fee - normally about $20.00 per order. I have bought Norma 202, 4227, Accurate #5 and #7. If you are on a budget this probably isn't for you because you need to order enough to spread the Hazmat out thinly enough to be palatable. Also, at an average of about $25 a pound it costs a lot to order much.
I looked at my sources today and was surprised by how many varieties of powder were available. Most online retailers have the ability to only list items that are in stock. A few do not and they take more time. But they do come through. I have been disappointed with the sites everyone knows like Midway. But others like MidSouth, Natches, Powder Valley, Precision Reloading, etc. often have something. If you know some I have missed please share.
Jim