Note that technically speaking there is no such thing as "Rifle Powder", "Pistol powder" or "Shotgun Powder". They are all simply smokeless propellant powders, but their main use is determined by their burning characteristics. Recent Alliant Reloaders guides list their powders & give "Principal Use" & then "Can Also Be Used In". I note that the lack of interest in such rifle calibers as the Hornet & Bee has caused a shift in "Principal Use" for 2400 from "Light Rifle" to "Magnum Handgun". "Can Also Be Used In" states "Some Rifle & Shotshell Loads". As well as the .410 it is also listed in a 1240fps 1¼oz load in the 3" 20ga & 12ga "Heavy" 3" buckshot & one 1525 fps 1oz Brenneke slug load. These loads are all in the 9k+ psi range with the ½oz 2½" .410 loads being in the 11-12K range & the 3" 11/16oz loads going 12-13K. I highly suspect any 2400 loads falling much below 9K psi would be asking for problems with squibs & such.
