unless you have a shock proof capsule in which to contain said item, the recoil and exit from bbl would disperse the item prior to delivery. if it was a solid unit them you would need to ensure that it was fast acting. your other issue is a hollow point starts to spread out upon contact (hopefully) depending on type of HP used and object it hit the answer is No it is not feasable.
a better bet is delivery via arrow or dart/blowgun.
setting up a round to deliver a more lethal device would possibly be considered premediated, as you were prior to force continuim contact prepared to end said life.
of course a lawyer can answer any and all questions in private, for a reasonable fee vs. putting your shit out there on the web for all to see.

if you were faced with multiple attackers and nothing was going to slow them down other than super lethal means. liquid or aerosolized delivery is the most effective means. this way it enters through any portal of entry. However the time of delivery vs, effects will vary depending on temp, distance from dispersal unit, are they wearing chemical mask etc.
myself i'd go for a HE charge