Revolver caliber changes; .357 revolvers can now also load .38 but not vice-versa.

Effectively it means you can load .38 rubber into a .357 revolver to make it less than lethal, or use the various different .38 ammo types.

code/modules/projectiles/boxes_magazines/internal/_cylinder.dm

@@ -1,7 +1,7 @@
 /obj/item/ammo_box/magazine/internal/cylinder
 	name = "revolver cylinder"
 	ammo_type = /obj/item/ammo_casing/a357
-	caliber = "357"
+	caliber = list("357","38")
 	max_ammo = 7
 
 /obj/item/ammo_box/magazine/internal/cylinder/ammo_count(countempties = 1)
@@ -31,7 +31,7 @@
 		rotate()
 
 /obj/item/ammo_box/magazine/internal/cylinder/give_round(obj/item/ammo_casing/R, replace_spent = 0)
-	if(!R || (caliber && R.caliber != caliber) || (!caliber && R.type != ammo_type))
+	if(!R || (caliber && !(R.caliber in caliber)) || (!caliber && R.type != ammo_type))
 		return FALSE
 
 	for(var/i in 1 to stored_ammo.len)

code/modules/projectiles/boxes_magazines/internal/grenade.dm

@@ -1,7 +1,7 @@
 /obj/item/ammo_box/magazine/internal/cylinder/grenademulti
 	name = "grenade launcher internal magazine"
 	ammo_type = /obj/item/ammo_casing/a40mm
-	caliber = "40mm"
+	caliber = list("40mm")
 	max_ammo = 6
 
 /obj/item/ammo_box/magazine/internal/grenadelauncher

code/modules/projectiles/boxes_magazines/internal/revolver.dm

@@ -1,19 +1,19 @@
 /obj/item/ammo_box/magazine/internal/cylinder/rev38
 	name = "detective revolver cylinder"
 	ammo_type = /obj/item/ammo_casing/c38
-	caliber = "38"
+	caliber = list("38")
 	max_ammo = 6
 
 /obj/item/ammo_box/magazine/internal/cylinder/rev762
 	name = "\improper Nagant revolver cylinder"
 	ammo_type = /obj/item/ammo_casing/n762
-	caliber = "n762"
+	caliber = list("n762")
 	max_ammo = 7
 
 /obj/item/ammo_box/magazine/internal/cylinder/rus357
 	name = "\improper Russian revolver cylinder"
 	ammo_type = /obj/item/ammo_casing/a357
-	caliber = "357"
+	caliber = list("357")
 	max_ammo = 6
 	multiload = 0