Outdoormarksman and Miwall are not the same company. Outdoormarksman is just a distributor for Miwall.
The Miwall site is down every now and then, but I always figured that they were just busy with gun shows. I looked at their gun show schedule and during 1 weekend, they were at 3 gun shows. But since Outdoormarksman is a different company, I would expect them to have the ammo in stock.
Anyway, I don't use other people's reloads (I can reload my own), but if I were going to, I'd be fine with using Miwall. They do lots of business at the gun shows here and I've never heard anyone complain about their ammo. I do buy primers, powder, Wolf 7.62x39, and Aussie .308 from them.