Concerning the first, have an excerpt from recipes.json:
{
"type" : "recipe_category",
"id" : "CC_WEAPON",
"recipe_subcategories" : [
"CSC_ALL",
"CSC_WEAPON_BASHING",
"CSC_WEAPON_CUTTING",
"CSC_WEAPON_PIERCING",
"CSC_WEAPON_RANGED",
"CSC_WEAPON_EXPLOSIVE",
"CSC_WEAPON_MODS",
"CSC_WEAPON_OTHER"
]
},{
In the recipe for the item, you’ll watnt to replace what I’m presuming is “CSC_WEAPON_OTHER” with “CSC_WEAPON_RANGED” to make it subcategorize correctly.
For the second, yes. Item groups are the big thing that makes most items in the game show up. Only other normal ways to encounter items are if they’re spawned specifically in a mapgen entry, or placed on an NPC equipment list.