How old is your IMR4350? Not asking to make sure it's still good, but I bought a couple pounds of IMR4350 a couple years ago, the stuff made in Canada, and it turned out to be "short-cut"! So far it has produced just about exactly the same velocities as the standard. long-granule IMR4350 that most veteran handloaders know so well.
Why would the powder manufacturers not make all stick powders short cut?
