Buff XM88 (#6375)

# About the pull request

This PR changes the XM88 to have comparable values as if the weapon had
a barrel charger attached to it, this includes a buff of its damage to
104, and a decrease to its inherent accuracy and rate of fire.

# Explain why it's good for the game

The removal of the barrel charger from the gameplay loop had the
unintended side-affect of indirectly nerfing the XM88 in a significant
manner. Prior to its removal the barrel charger was a "must-have"
attachment for the weapon, as it brought its damage up to a level of
greater lethality, wherein without it the weapon now struggles more so
against hardened targets. Furthermore, the weapons higher skill
requirement means that you will regularly miss shots on a target, thus
the weapon having a higher damage upfront rewards you for landing your
shots.

To account for this, this PR effects the change to presume the weapon is
under the benefits and drawbacks of having a barrel charger attached to
it. Meaning the gun has a higher damage per bullet but suffers a rate of
fire decrease and a major decrease in its accuracy.

Functionally this is bringing the weapon back to its older state that
was what the majority of the player base grew to expect the weapon to
perform.

Due to the major nerfs to the extended barrel, the now ability to attach
it to this weapon comports a almost non-existant boon to the weapon and
thus is not a point of balance contention.

Furthermore, after doing some offline testing I can ascertain that the
average time-to-kill on a stationary target in white-room conditions is
almost virtually unchanged. For example, a Warrior can expect to be dead
in 8 seconds from both the original and this new version. The difference
really comes down to the weapon having slightly higher damage up-front
if you do land your shot.


# Testing Photographs and Procedure
<details>
<summary>Screenshots & Videos</summary>

Put screenshots and videos here with an empty line between the
screenshots and the `<details>` tags.

</details>


# Changelog
:cl:
balance: The XM88 now deals higher damage per-bullet at the cost of a
slightly lower rate of fire and accuracy. This is identical to as if it
had a barrel charger attached to it.
balance: Per the above, the barrel charger is no longer compatible with
the XM88.
/:cl:

---------

Co-authored-by: Steelpoint <[email protected]>

code/datums/ammo/bullet/lever_action.dm

@@ -52,7 +52,7 @@
 /datum/ammo/bullet/lever_action/xm88
 	name = ".458 SOCOM round"
 
-	damage = 80
+	damage = 104
 	penetration = ARMOR_PENETRATION_TIER_2
 	accuracy = HIT_ACCURACY_TIER_1
 	shell_speed = AMMO_SPEED_TIER_6

code/modules/projectiles/guns/lever_action.dm

@@ -378,7 +378,6 @@ their unique feature is that a direct hit will buff your damage and firerate
 		/obj/item/attachable/bayonet/upp, // Barrel
 		/obj/item/attachable/bayonet,
 		/obj/item/attachable/extended_barrel,
-		/obj/item/attachable/heavy_barrel,
 		/obj/item/attachable/suppressor,
 		/obj/item/attachable/compensator,
 		/obj/item/attachable/reddot, // Rail
@@ -393,9 +392,9 @@ their unique feature is that a direct hit will buff your damage and firerate
 
 /obj/item/weapon/gun/lever_action/xm88/set_gun_config_values()
 	..()
-	set_fire_delay(FIRE_DELAY_TIER_2)
+	set_fire_delay(FIRE_DELAY_TIER_2 + FIRE_DELAY_TIER_11)
 	lever_delay = FIRE_DELAY_TIER_3
-	accuracy_mult = BASE_ACCURACY_MULT + HIT_ACCURACY_MULT_TIER_5
+	accuracy_mult = BASE_ACCURACY_MULT + HIT_ACCURACY_MULT_TIER_2
 	accuracy_mult_unwielded = BASE_ACCURACY_MULT - HIT_ACCURACY_MULT_TIER_10
 	scatter = SCATTER_AMOUNT_TIER_8
 	burst_scatter_mult = 0