Pappy,
Ha! Actually I've been suggesting switching to IMR4451 for more than a year now. It was also recently in short supply, which Hodgdon tells me was also due to 6.5 Creedmoor users, but is now in stock at several places. In fact I just received a recently ordered 8-pounder, even though I'd just opened another, because I'm going through 4451 like I used to go through H4350. Haven't found a cartridge/load combination yet where 4451 doesn't work as well as H4350, and in some it's worked better.