Slow rust bluing is much easier than it sounds, and would produce beautiful results...plus the satisfaction of restoring your piece with your own hands. I recommend Mark Lee's express blue if you want it done in a day. Excellent results. You will find reports of difficulty with some of the winchester nickel steel. This can be solved by pre-etching with a correct solution. All you need, and need to know on that, is here https://www.rustblue.com/blog/rust-bluing-woes/. I have used their solutions before with good results, but indistinguishable from the results I have with Mark Lee's express...so now I prefer to blue for a Saturday instead of a week or 2.