Honestly I cannot recall what I blacked my rifle with, but it's obvious that I did, and I'll do it again.
Why post you ask? Well because this stuff, especially the finishing, is never going to be plug-n-play, or one size fits all. Test on scrap or where you can scrape off and start over. The more you do, the more you find out.
Sorry if you don't find that helpful, but is the intent. Also that there's a myriad of ways to make up a finish. One quite common process used by those who prefer an aged look is to "overfinish" and rub back. More than once for best effect.