I don't know if Buffalo Bullet got back up and running. Their website says they were to be back in production in 2Q 2019, but I don't see anything else that makes it look like they are producing. They have a FB page, but since I don't have a FB account, I can't look at anything, and believe me, I'm not getting a FB account just to find out! No FB...no tweeting...nothing!
If they are producing their old 54 Buffalo bullet, that's as close to a Hornady GP as you can get.
I actually have 1 unopened box of the 54 GP plus 9 more in an opened box. We can talk via PM if you are interested. I also have a full box of 50 310 gr Buffalo Ballets plus an open box with 9 more. I have 3 boxes of the TC Hunters in 54 as well (one of those might be a partial).
But long term, looks like you'll need to start molding up your own REAL's.