Not sure if anyone is looking for 7.62x51 but SGAmmo has a few cases of Magtech available. I've been looking without much luck, so thought I'd throw this out there...
I just checked and your right it's not there. They must have sold out over night. There were about 24 cases when I posted it up. If I see it become available again, I'll post the link.
It shows 0 available but you can hit notify me when back in stock. I did this the last time and within 2-3days I got an email saying they had some. It sold out in about 24hours.