For those who don't already know, Hodgdon 4227 is no longer made. Only imr4227 is now available. Many of the best loads developed for the Herrett used the Hodgdon powder. Comparing the 2009 Hodgdon manual to the RCBS cast bullet manual number one, there are some large disparities in the published data for the IMR data. RCBS shows a maximum load of 28 grains of IMR for a 162 grain cast bullet and a max of 27 grains for a 175 grain cast bullet. Meanwhile, the Hodgdon manual shows a max load of 20.2 grains of IMR with a 158 grain jacketed bullet and 20.1 grains with a 170 grain jacketed bullet. This seems like a rather large difference in powder charges. I realize the cast bullet will generate less pressure, but I am surprised to see that it is that much different. Even the old Lyman 46th shows max loads with IMR of 20.5 wit 155 gr cast, and 19.5gr with 168gr cast. Any comments from the peanut gallery?