This was an unnamed spherical rifle propellant when Bruce ?B.E.? Hodgdon first used it. When a 38.0 grain charge behind a 52 grain bullet gave one hole groups from his 22-caliber wildcat (now called the 22-250), he appropriately named the powder H380. H380 is also a superb performer in the 220 Swift, 243, 257 Roberts and other fine varmint cartridges.
Check your reloading manual or go to a powder manufactures website for load data.