We've opened up the Blackrock Foundry raid on the 6.1 PTR for the weekend. The first boss(es) of each wing are accessible (Oregorger and Gruul in the Slagworks; Hans'gar and Franzok in the Black Forge; and Beastlord Darmac in the Iron Assembly), on Normal difficulty only. Use the Group Finder to find some like-minded allies, get in there, and check out a bit of the raid zone that's coming to live servers in less than two weeks!
Organized guilds should keep an eye on the PTR forums next week for a couple of more targeted tests of specific bosses on higher difficulties.
Please use this thread to provide feedback on the four available Foundry bosses. Item level will be scaled to 650 for the purposes of the test. When providing feedback, please specify the size and nature of your group (pure PUG, Mythic raiding guild, etc.), and remember that these are the first bosses of the zone on Normal difficulty. The intended tuning target here is in the ballpark of Highmaul bosses like Butcher or Twin Ogron on Normal difficulty.