Jackal is obtained much later in the game and it can't be silenced, disallowing you to complete a mission stealthily.
Dunno if it's different in singleplayer, but I think all silenced weapons start losing damage after about 15 meters, but 15m is already beyond effective range of Marshall so it's not affected.
I also heard a rumor that the under barrel shotgun deals damage of Marshall and Jackal combined. It might be true as it does great damage to Ceph and has very low range in mp but can take down armored opponent in 1 precise shot.
If u carry a rifle with this shotgun attached and another shotgun as secondary weapon u get like 24-28 shots for it.
PS: Real men use pump-action shotguns.