IMR 4831 is just a smidge faster than H-4831.
.4301 H-4831
.4421 IMR-4831
So, being this close, if you can't find H-4381 SC maybe the IMR 4831 is not a bad substitute, though there may be cut/size differences in the granular size of the powders.
.4301 H-4831
.4421 IMR-4831
So, being this close, if you can't find H-4381 SC maybe the IMR 4831 is not a bad substitute, though there may be cut/size differences in the granular size of the powders.