Has anybody done it? Ive been trying but the rust wont convert to black no matter how long I boil it. Ive given it about 30 cycles, and its only a light grey. Briwnells says just keep going, its their formula im using but its a couple of years old. I called anther comany tday that makes rust bluing solution and he told me Rugers dont rust blue because they are cast.

Im using distilled water to boil.

Have not tried to rust blue Rugers but have blued many with conventional hot blue.
The older ones re particularly hard to get a deep black color.Normally blue at 280f and with the older cast receivers typically 300-310. It's a fine line. Not hot enough and you will get a dull black/gray too hot you will get a rust red film that can only be buffed off. Essentially start over.
Rugers can be a PIA.

Lefty C

That high nickel content 8620 steel is hard to blue and make dark. Even then it will start to turn plumb color in time. Even factory bluing will start to turn plumb over time. I will bet the cylinder and barrel will rust blue normally since they are not cast.

I rust blued a Ruger #1 with Laurel Mountain Forge Barrel Brown and Degreaser. The receiver did not color nearly as well as the barrel. It remained grayish-black while the barrel and lever came out a nice blue-black. Since the lever is also cast, I don't think investment casting has any effect on bluing. However, the steel alloy certainly does.

I did have a New Mod. Blackhawk charcoal blued and the frame came out a very nice dark blue-black, essentially matching the cylinder and barrel. So, there is a way to get a good blue besides ordinary hot salts bluing.

RAN

Neither the barrel nor the cylinder converted well. Im wondering if the brownells solution has gone bad? Does the solution matter or is rust rust?

The solution composition makes a difference according to what I have read. The experts also say the the heat-treatment condition of the metal makes a difference. I agree with that. In my experience, the modern alloy steels like 4140 are difficult to rust blue. The straight carbon steels in old guns usually rust blue nicely unless they have been previously case hardened. If you don't get a good blue in 6 rusting cycles, you are wasting your time

I doubt the solutions go bad with age since they are usually nothing but dilute acid and water. I have always used the Laurel Mtn. solution since it contains a detergent, making it much easier to use. There is no need to have perfectly clean metal when applying the solution or when carding. What I mean is, fingerprints are no problem. This allows bare-handing the parts with no worries about spotting the finish.

RAN

I'm bummed I won't get the rust blued finish I wanted. I have all the equipment already so I guess I'll go to my fallback position and cerakote it. I just need to get the "paint". What does the graphite black look like?

I'd guess the investment casting is the culprit. The rust bluing I've done on Mausers always come out great.

Back long ago I got guns blued at Cleveland Black Oxide and on the shelf were very thick books with every gun ever made and a formula for the salts needed for each steel.
Rust blue a Ruger???

Mausers rust blue nicely because they are made from plain carbon steel with none of the chrome, nickel, or moly used in more modern hi-tensile alloys like 4140 or 4340.

RAN

I rust blued a Mauser that has a Midway barrel on it. I didn't have any issues. That's why I tackled the Blackhawk. Totally different experience.