ORIGINAL: eldeguello
It's quite simple why you find no loads for the 7 Mag. using IMR 4064-that powder is too fast for the big case. I suppose you could use light loads of it in the 7 Mag., but it doesn't fill up the case very well before you get to maximum, so accuracy might not be too good.
Actually my book has a 150 and a 175gr load for 4064. Just no 160. I agree ,though its probably not the most appropriate powder for a large case.