H4350 and IMR4350 are very close... but slightly different in burn rate.  Most reloading manuals will state whether the data is for IMR, Hogdon, Accurate, etc., and you will see a difference.  When consulting your load tables, make sure you are using data for IMR4350 if you're using IMR powder, H4350 data if using Hogdon powder, etc. - and you won't go wrong.  FWIW, I use IMR4350 in my Krag competition loads.