Winchester WSF Smokeless Powder 4 Lb is the propellant of choice for Winchester 20 gauge AA Target loads. WSF is an ideal choice to maximize velocities in 12 gauge 1-1/8 ounce and 1-1/4 ounce loads. Super-Field also performs well in 38 Super, 9mm, and 40 S&W pistol loads. Excellent propellant for action pistol applications. Grain shape is irregular flat ball.