I have used both. The Oxpho blue worked the best for me. Warming up the metal with a blow dryer helped and after I had the color I wanted I soaked it all down with WD40 and I mean soaked. I let it sit and kept am eye on it for a week before reassembling. A couple months later and 100 rounds still looks good.

 

Thanks I have 5 cans of WD40 around, I'll give that a shot.

 

I have done a .22 and a .410 with the Oxpho Blue and both look good.

 

Carl cold blueing for the most part is for small areas and will probably not give you the results you are looking for. it will continue to have rust spots. the best way is going to be finding someone who can hot blue it for you, or try some of the spray on coatings like DuraCoat or others. part of the problem with cold bluing products is not getting an even coverage like being able to immerse the entire part into the blueing solution. from what i understand the Oxphos from Brownell's is probably one of the best cold blueing solutions and if you have a way to immerse the entire part to blue it, then your results will be much better. good luck.

 

After a hot blue bath the guns go to a neutralizing bath then oil bath. Cold blue needs the same but seldom do people neutralize the cold blue. The WD-40 idea above would do that job fine.