The "Field" sitting position.
For competition use the Crossed Legged position is greatly preferred, as it is the most stable of the seated positions. For field shooting, or informal target shooting, the open legged position is almost as steady, and allows for a much greater field of regard. Useful when shooting multiple targets instead of a single bull.
Note how the subjects elbows are forward of the knees, locking in support. By repositioning the feet one can change the natural point of aim.
Rifle is a Remington Model Five (made by Zastava), and yes I really should add sling swivels and a model 1907 sling.
Bonus points to the first person to correctly identify the revolver.