It seem that with the discontinuation of the SR powders and PB Hodgdon is bringing IMR back to it's roots, Improved Rifle Powders. (not pistol or shotgun powders)
If you look at the IMR and Hodgdon sited you will moved they moved 700x, 800x, Trail Boss and PB over to the Hodgdon site. A few weeks ago the three SR powder were on the Hodgdon site too but for some reason they moved them back to the IMR site. (not that it matters since they will be gone soon anyway)