New Bunker Buster CAS Missile: GBU-67-EP 'Paveway XXI'

code/game/machinery/computer/dropship_weapons.dm

@@ -321,7 +321,7 @@
 							is_outside = TRUE
 						if(CEILING_GLASS)
 							is_outside = TRUE
-				if(!is_outside && !cavebreaker) //cavebreaker doesn't care
+				if(!is_outside && !(selected_equipment.ammo_equipped.ammo_ignore_caves)) //cavebreaker doesn't care
 					to_chat(usr, SPAN_WARNING("INVALID TARGET: target must be visible from high altitude."))
 					return
 				if (protected_by_pylon(TURF_PROTECTION_CAS, TU))

code/modules/cm_marines/dropship_ammo.dm

@@ -38,6 +38,8 @@
 	/// Mob that fired this ammunition (the pilot pressing the trigger)
 	var/mob/source_mob
 	var/combat_equipment = TRUE
+	var/ammo_ignore_caves = FALSE
+	/// Ignores Caves when lining up FMs
 
 /obj/structure/ship_ammo/attack_alien(mob/living/carbon/xenomorph/current_xenomorph)
 	if(unslashable) 
@@ -321,6 +323,22 @@
 		cell_explosion(impact, 450, 100, EXPLOSION_FALLOFF_SHAPE_EXPONENTIAL, null, create_cause_data(initial(name), source_mob)) //Insane fall off combined with insane damage makes the Keeper useful for single targets, but very bad against multiple.
 		qdel(src)
 
+/obj/structure/ship_ammo/rocket/bunker_buster
+	name = "\improper GBU-67-EP 'Paveway XXI'"
+	desc = "The GBU-67-EP 'Paveway XXI' takes the GBU-67 LGB and mates it with an enhanced penetrator warhead that allows it to strike targets dozens of meters underground."
+	icon_state = "bunkerbuster"
+	travelling_time = 20 //A fast payload due to its very tight blast zone
+	ammo_id = "p"
+	point_cost = 600
+	ammo_ignore_caves = TRUE
+	fire_mission_delay = 0 //no FMs, direct only
+
+/obj/structure/ship_ammo/rocket/bunkerbuster/detonate_on(turf/impact)
+	impact.ceiling_debris_check(5)
+	spawn(5)
+		cell_explosion(impact, 450, 100, EXPLOSION_FALLOFF_SHAPE_EXPONENTIAL, null, create_cause_data(initial(name), source_mob)) //See Keeper comments: However this is able to penetrate cave ceilings.
+		qdel(src)
+
 /obj/structure/ship_ammo/rocket/harpoon
 	name = "\improper AGM-84 'Harpoon'"
 	desc = "The AGM-84 Harpoon is an Anti-Ship Missile, designed and used to effectively take down enemy ships with a huge blast wave with low explosive power. This one is modified to use ground signals."