I've got some Sierra 220gr round nose Pro Hunter bullets and most of a pound of 1680 you can have to play around with.
Give me a day or so and I'll find the load data for my .300 loads. They are subsonic and I've never really tested them past 50yds but it's an accurate load out of my 10.5 SBR with a 1in8 twist barrel.
I'd like to hear a range report if you ever get your hands on some.
If you don't want/need them anymore I'll take em. You getting out of .300 BLK?
... these are getting ladder loaded and taken out to 200 yds. I'll post some results when I finally get to shoot them.