Gus: I do not "know" how the shot exits the thin plastic shot capsule?
I do know that for the last 30 - 35 years it does disperse somehow, and will kill Rattlesnakes - it usually takes 3 - 4 head shots from a 22 L.R. revolver or 2 - 3 head shots from a 22 Magnum revolver.
Buy them and set up a thin cardboard "backboard" starting at say 3 yards then 5 yards then at 7 yards and see at what range the shot appears to have left the capsule.
That might work to help give some insight on your question?
Anyway they work's - I just don't know the answer to your inquiry.
Hold into the wind
VarmintGuy