a bb fired from a red ryder bb gun has more velocity, energy, penetration, and lethality then each individual pellet released upon impact by a glaser slug.
the issue is that glasers can make a nice entrance hole, and surface wound, but look at the gelatin testing done. even in bare gelatin thereis a consistent lack of wound channel past the first 2 inches.
so in theory, if your opononent is emaciated and only 4 inches thick, then you could reach vital organs. but if your opononent has been living on pork chops and the golden arches of grease for 20 years and hase 7 inches of spare tire on the outside, dont expect much.