Yes, Fred,
I noticed the deficient velocity and foot pounds distribution and sectional density coeffient of the projectiles when a low shot bounced off a wing and the chicken clucked at me in indignation and flew off. The next time I go to the range I am going to chronograph my marbles, and compare them to steel and lead balls for velocity.
Problem is that I am sighted in for the glass marbles and may have to readjust my sights.