Did you try track of the wolf or log cabin shop? Tip Curtis Frontier shop might be another place.

If they did go out of business that just sucks. I have used their rust blue and I do like it.  I have been playing some with another rust blue product called Rust Blue. I have what they list as the "American Blue". Yes you have to keep things clean but it seems to work well. 
What I have done is polish 3 pieces of barrel to 800, 1000 and 1200 and then run them all at the same time. So far I have done 7 cycles with the parts being steamed instead of boiled. The 800 has come out very nice, the 1000 is good but could use a few more cycles as does the 1200.  I just don't let them get a thick coat of rust, I just stop at a very fine brown fuzz. 
Sam

That's what I've been using for years. I hope this is not true as I would not like to have to start over.

Ordered a three different humidity rusting products.
Now,to see which one works best.

Deadeye Bly, could you send me a nice new barrel to practice on??😂
Thanks,
Tom Klinger