The 7 saum dies struggle a little. The problem with dies is they warp in the hardening process so you may get one that works and you may get one that doesnt. The Micron dies are nice because they are nitrided, so almost no warp to deal with. Hornandy makes good custom dies too, I have had them make me a bunch of them and so long as you give them good specs they work well. Thats the key, you need to figure out the right specs first. Do not rely on the die makers to spec them. I spec'd out a 7 saum die for a customer and they just shipped him a batch. After he runs them a little bit I told him he should order a bunch and sell them. Theres a huge market out there for dies that actually work. My business plan usually goes like this, spend a couple grand on re size reamers and make a bunch of dies until I figure it out, then give it away for free
I would bet Bullet Central will make 7 saum dies too if enough guys ask.