The graver shown is what is called a 'Liner Graver'.
They are generally used for shading the engraved pattern and other accents. Some work uses a Liner to remove the background from the scroll work for a relief cut pattern
For this background removal, some engravers cut the lines all parallel with each other. Others use the liner in a random cut.
(Wm. Gough often used a Liner for scroll background work.)
The Liner gravers cut multiple lines, but they are usually so fine in nature that they do not produce a noticeable checkering type pattern. When used criss-cross they call the cut a
Forentine cut. That is used a lot in jewelry engraving but has it's use in firearms engrv'g too.
The liners are sold by width of the graver and the number of lines a particular width will cut.
There are many, many different #'s of Liners all the way from cutting just 2 lines (useful for those double line borders) up to very fine multi line cut.
If you can find one that cuts a coarse enough line spacing then it can be used for a checkered look pattern such as a top rib.
Liners are generally HS steel gravers, so they can lose their point rather quickly especially on some of todays steel used in guns.
