Slow Rust Bluing Recipe

[bigduke6]

2% ammonium chloride would be diluted in destilled water?

Distilled or rain water. I would recommend to test on some scrap steel, try two bits, one highly polished and one sand blasted or similar. As Topfmine describes it is a deep black /blue finish.
Common table salt can be used but gives a brown / black finish IIRC.

The only things I blue now are bayonets ........ all other stuff normally gets blasted and a parkerised/ phosphate finish.

You won't be disappointed in the book.