Adds Armor-Piercing 9mm Magazines to the game (#20815)

-Adds Armor Piercing 9mm Ammo along with Pistol Magazines for it.

-It currently deals 12 damage and has 30 Armor-Penetration, allowing it
to deal more damage than .45 to armored opponents however it struggles
against unarmoured targets due to it's low damage output

Only available on the Antagonist Uplinks for now.


![9mmap2](https://github.com/user-attachments/assets/81b9f758-8e8e-4f0b-ad8a-b399c5fabd60)

---------

Signed-off-by: Birigilis <kavbest10@gmail.com>
Signed-off-by: Matt Atlas <mattiathebest2000@hotmail.it>
Co-authored-by: Matt Atlas <mattiathebest2000@hotmail.it>
Co-authored-by: SleepyGemmy <99297919+SleepyGemmy@users.noreply.github.com>

code/modules/projectiles/ammunition/boxes.dm

@@ -212,6 +212,15 @@
 /obj/item/ammo_magazine/mc9mm/empty
 	initial_ammo = 0
 
+/obj/item/ammo_magazine/mc9mm/polymer
+	name = "magazine (9mm polymer)"
+	icon_state = "9x19AP"
+	mag_type = MAGAZINE
+	caliber = "9mm"
+	ammo_type = /obj/item/ammo_casing/c9mm/polymer
+	max_ammo = 12
+	multiple_sprites = 1
+
 /obj/item/ammo_magazine/mc9mm/flash
 	name = "magazine (9mm flash)"
 	ammo_type = /obj/item/ammo_casing/c9mm/flash

code/modules/projectiles/ammunition/bullets.dm

@@ -47,6 +47,12 @@
 	caliber = "trod"
 	projectile_type = /obj/projectile/bullet/trod
 
+/obj/item/ammo_casing/c9mm/polymer
+	desc = "A 9mm polymer bullet casing."
+	caliber = "9mm"
+	projectile_type = /obj/projectile/bullet/pistol/polymer
+	max_stack = 15
+
 /obj/item/ammo_casing/c9mm
 	desc = "A 9mm bullet casing."
 	caliber = "9mm"

code/modules/projectiles/projectile/bullets.dm

@@ -181,6 +181,10 @@
 	damage = 20
 	armor_penetration = 15
 
+/obj/projectile/bullet/pistol/polymer
+	damage = 12
+	armor_penetration = 30
+
 /obj/projectile/bullet/pistol/medium
 	damage = 30
 	armor_penetration = 0