Mike Brooks' tutorial is what most likely gave the OP the idea, but not the detailed methodology. Here's what works for me. First, make sure you've adequately sealed the wood with linseed oil or whatever you use for finish coating; the last thing you want is the paint to permeate the wood. The paint is relatively easy to rub back provided the wood is sealed well. Once you've sealed the grain, hit the stock with flat black spray paint. Make sure it is FLAT black; the $1.00 Home Depot rattle cans work fine. In addition to being the right choice for the look, flat black is very forgiving as it doesn't have a tendency to run and covers easily. One coat will do, but ensure the whole stock is covered. Let the stock dry for at least 2-3 hours. Flat colors also dry quickly, so you can work with the paint in relatively short order. You can let it sit as long as you want (after the 2-3 hours), btw, it won't make the paint harder to remove. When you're ready, take some 0000 steel wool and start rubbing back the paint with a gentle but firm circular motion (you don't want to cut through your finish to your stain) Start in the middle of an area and work towards the crevices, carvings and inlays. As you get closer to an area where the black is to be concentrated, lighten up on the presssure to feather the black along the perimeter of that area. You can rub right over dings and dents as the black will settle in those spots nicely. Once you're satisfied with your work, finish the wood with coats of linseed oil or whatever you use. This is a wonderful trick that imparts a look similar to real patina. You'll no doubt be quite proud of your efforts.
Smollett