I used half of bottle blacken my barrel over and over never got black dark
I bought the Blue Wonder blueing kit about 5 years ago for a small job and never left a review....
I recently bought an old Anschutz 22 rifle that was very rusty and had about 1/2 it's bluing left.
Using the 5 yr old opened kit, I followed the instructions and heated the barrel with a heat gun,
and applied the Blue Wonder.... it came out Amazing....looks like new from about 2 feet away...
( My only critique it that the instructions don't say how to use the developer liquid....I put it on after
the barrel cooled and left it on for 3 hours ) I oiled it heavily with Kroil and was ready to use the next day.
I wouldn't use any other blueing after these results !!!