It IS possible to do a bluing job yourself--even hot tank bluing--but there are some things you must be aware of:
1. The equipment to do it properly is expensive. Brownell's does sell a complete bluing outfit--but the beginning equipment will set you back at least $900 or more.
2. In a bluing job, metal prep and proper flaw removal is EVERYTHING. You'll need more tools for that, so bargain in another $600 or so--at the very least.
3. You will find it VERY difficult--if not impossible--to duplicate Royal Blue. The original Royal Blue was known as carbonia bluing, and I believe it involves the use of arsenic.
Hiding in plain sight...