Hopefully this will add in the missing WT-550 Toxin Ammo for sec to use! (Combat medics will use this to heal slime's more then likely as well)

code/modules/projectiles/boxes_magazines/external/smg.dm

@@ -14,6 +14,10 @@
 	icon_state = "46x30mmtA-20"
 	ammo_type = /obj/item/ammo_casing/c46x30mm/ap
 
+/obj/item/ammo_box/magazine/wt550m9/wttx
+	name = "wt550 magazine (Toxin Tipped 4.6x30mm)"
+	ammo_type = /obj/item/ammo_casing/c46x30mmtox
+
 /obj/item/ammo_box/magazine/wt550m9/wtap/update_icon()
 	..()
 	icon_state = "46x30mmtA-[round(ammo_count(),4)]"

code/modules/research/designs/weapon_designs.dm

@@ -230,6 +230,14 @@
 	build_path = /obj/item/ammo_box/magazine/wt550m9/wtap
 	departmental_flags = DEPARTMENTAL_FLAG_SECURITY
 
+/datum/design/mag_oldsmg/tx_mag
+	name = "WT-550 Auto Gun Uranium Magazine (4.6x30mm TX)"
+	desc = "A 20 round uranium tipped magazine for the out of date security WT-550 Auto Rifle"
+	id = "mag_oldsmg_tx"
+	materials = list(MAT_METAL = 6000, MAT_SILVER = 600, MAT_URANIUM = 2000)
+	build_path = /obj/item/ammo_box/magazine/wt550m9/wttx
+    departmental_flags = DEPARTMENTAL_FLAG_SECURITY
+
 /datum/design/mag_oldsmg/ic_mag
 	name = "WT-550 Auto Gun Incendiary Magazine (4.6x30mm IC)"
 	desc = "A 20 round armour piercing magazine for the out of date security WT-550 Auto Rifle"

code/modules/research/techweb/all_nodes.dm

@@ -588,7 +588,7 @@
 	display_name = "Ballistic Weaponry"
 	description = "This isn't research.. This is reverse-engineering!"
 	prereq_ids = list("weaponry")
-	design_ids = list("mag_oldsmg", "mag_oldsmg_ap", "mag_oldsmg_ic")
+	design_ids = list("mag_oldsmg", "mag_oldsmg_ap", "mag_oldsmg_ic", "mag_oldsmg_tx")
 	research_costs = list(TECHWEB_POINT_TYPE_GENERIC = 2500)
 	export_price = 5000