Nerfs merc sniper rifle and makes it uplink purchasable

Also reduces the Z8's damage a bit, just to make it more in line with
the new bullet damage ranges.

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

@@ -1,6 +1,6 @@
 /obj/item/weapon/gun/projectile/heavysniper
 	name = "\improper PTRS-7 rifle"
-	desc = "A portable anti-armour rifle fitted with a scope. Originally designed to used against armoured exosuits, it is capable of punching through non-reinforced walls with ease. Fires armor piercing 14.5mm shells."
+	desc = "A portable anti-armour rifle fitted with a scope. Originally designed to used against armoured exosuits, it is capable of punching through windows and non-reinforced walls with ease. Fires armor piercing 14.5mm shells."
 	icon_state = "heavysniper"
 	item_state = "shotgun"
 	w_class = 4

code/modules/projectiles/projectile/bullets.dm

@@ -141,13 +141,13 @@
 	penetrating = 1
 
 /obj/item/projectile/bullet/rifle/a145
-	damage = 80
+	damage = 60
 	stun = 3
 	weaken = 3
 	penetrating = 5
 
 /obj/item/projectile/bullet/rifle/a556
-	damage = 50
+	damage = 40
 	penetrating = 1
 
 /* Miscellaneous */