Here is the full list of all 15 TMM: Entourage achievements.
Kill 100 enemies with Arquebus
Destroy 100 enemies with Blunderbuss
Kill 100 enemies with Cane Gun
Kill 100 enemies with Carbine
Kill 100 enemies with Composite Bow
Kill 100 enemies with Harmonica Gun
Kill 100 enemies with Hidden Gun
Kill 100 enemies with Jezail
Kill 100 enemies with Longbow