Killing rats along the berm at night we used the M79. The buckshot round was relatively puny and popping off the cap, dumping the pellets the plastic sabot would kill them just as well.
This is a cross section of buckshot loading. The actual payload is relatively small and is contained within a central cushioned cup and is closed by a snap fit cap. The sabot cup has a rear facing post for support and has 6 hollow cavities around the exterior perimeter to both lighten and cause drag assist in payload separation. Since the M79 is rifled the spinning plastic made a noticeable whistling sound when fired that a grenade did not. The spin also opened up the pattern considerably. At 15 meters it was already a couple of feet in diameter At that distance the pellets would only dent a .50 caliber ammo can, not penetrate it.
https://www.milsurps.com/images/impo...mo09sepa-1.jpg