The last commit.

code/modules/projectiles/ammunition/boxes.dm

@@ -165,6 +165,19 @@
 	name = "top mounted magazine (9mm practice)"
 	ammo_type = /obj/item/ammo_casing/c9mmp
 
+/obj/item/ammo_magazine/p90
+	name = "high capacity top mounted magazine (9mm armor-piercing)"
+	icon_state = "p90"
+	mag_type = MAGAZINE
+	ammo_type = /obj/item/ammo_casing/c9mm/ap
+	matter = list(DEFAULT_WALL_MATERIAL = 3000)
+	caliber = "9mm"
+	max_ammo = 50
+	multiple_sprites = 1
+
+/obj/item/ammo_magazine/p90/empty
+	initial_ammo = 0
+
 /obj/item/ammo_magazine/clip/c9mm
 	name = "ammo clip (9mm)"
 	icon_state = "clip_pistol"
@@ -200,17 +213,7 @@
 	initial_ammo = 0
 
 ///////// 5mm /////////
-
-/obj/item/ammo_magazine/c5mmt
-	name = "top mounted magazine (5mm)"
-	icon_state = "p90"
-	mag_type = MAGAZINE
-	ammo_type = /obj/item/ammo_casing/c5mm
-	matter = list(DEFAULT_WALL_MATERIAL = 3000)
-	caliber = "5mm"
-	max_ammo = 50
-	multiple_sprites = 1
-
+/*
 /obj/item/ammo_magazine/c5mm
 	name = "magazine (5mm)"
 	icon_state = "fiveseven"
@@ -230,7 +233,7 @@
 	matter = list(DEFAULT_WALL_MATERIAL = 540) // metal costs are very roughly based around one 5mm casing = 60 metal
 	max_ammo = 9
 	multiple_sprites = 1
-
+*/
 ///////// 10mm /////////
 
 /obj/item/ammo_magazine/a10mm

code/modules/projectiles/ammunition/bullets.dm

@@ -29,6 +29,10 @@
 	caliber = "9mm"
 	projectile_type = /obj/item/projectile/bullet/pistol
 
+/obj/item/ammo_casing/c9mm/ap
+	desc = "A 9mm armor-piercing bullet casing."
+	projectile_type = /obj/item/projectile/bullet/pistol/ap
+
 /obj/item/ammo_casing/c9mmf
 	desc = "A 9mm flash shell casing."
 	caliber = "9mm"
@@ -47,10 +51,12 @@
 	icon_state = "r-casing"
 	projectile_type = /obj/item/projectile/bullet/pistol/practice
 
+/*
 /obj/item/ammo_casing/c5mm
 	desc = "A 5mm bullet casing."
 	caliber = "5mm"
-	projectile_type = /obj/item/projectile/bullet/pistol/small
+	projectile_type = /obj/item/projectile/bullet/pistol/ap
+*/
 
 /obj/item/ammo_casing/c45
 	desc = "A .45 bullet casing."

code/modules/projectiles/guns/projectile/automatic.dm

@@ -301,7 +301,7 @@
 
 /obj/item/weapon/gun/projectile/automatic/p90
 	name = "personal defense weapon"
-	desc = "The H90K is a compact, high capacity submachine gun produced by Hephaistos Industries. Despite its fierce reputation, it still manages to feel like a toy. Uses 5mm rounds."
+	desc = "The H90K is a compact, high capacity submachine gun produced by Hephaistos Industries. Despite its fierce reputation, it still manages to feel like a toy. Uses 9mm rounds."
 	icon_state = "p90smg"
 	item_state = "p90"
 	w_class = 3
@@ -310,8 +310,8 @@
 	slot_flags = SLOT_BELT // ToDo: Belt sprite.
 	fire_sound = 'sound/weapons/Gunshot_light.ogg'
 	load_method = MAGAZINE
-	magazine_type = /obj/item/ammo_magazine/c5mmt
-	allowed_magazines = list(/obj/item/ammo_magazine/c5mmt)
+	magazine_type = /obj/item/ammo_magazine/p90
+	allowed_magazines = list(/obj/item/ammo_magazine/p90, /obj/item/ammo_magazine/mc9mmt) // ToDo: New sprite for the different mag.
 
 	firemodes = list(
 		list(mode_name="semiauto", burst=1, fire_delay=0),

code/modules/projectiles/projectile/bullets.dm

@@ -128,9 +128,9 @@
 /obj/item/projectile/bullet/pistol
 	damage = 20
 
-/obj/item/projectile/bullet/pistol/small
-	damage = 15
-	armor_penetration = 50
+/obj/item/projectile/bullet/pistol/ap
+	damage = 20
+	armor_penetration = 30
 
 /obj/item/projectile/bullet/pistol/medium
 	damage = 25