I agree. As its burning rate is pretty much the same as either, it would likely serve as a good substitute for IMR and H4350. It does appear to offer some advantages over the other two. I did a bit more digging on this powder. According to IMR, 4451 powder features small kernels, which should allow for easy metering. Is temperature insensitive. Plus it has a copper inhibitor in it. Presumably this should reduce copper fouling in the bore. A bonus for anyone who shoots mono-metal bullets a lot. It does seem to have a fairly wide application range. Among the list, magnum cartridges like: 7mm Mag. 300 Winmag, 338 Winmag. Plus a bunch more standard cartridges, ie: 270, 30-06, etc. This new series of IMR powders might represent a new, enhanced level of performance in metallic cartridge reloading.