diff --git a/code/datums/ammo/bullet/sniper.dm b/code/datums/ammo/bullet/sniper.dm
index 6d0f0792ec53..0f4f2d89e2f1 100644
--- a/code/datums/ammo/bullet/sniper.dm
+++ b/code/datums/ammo/bullet/sniper.dm
@@ -106,11 +106,61 @@
 	accuracy = HIT_ACCURACY_TIER_8
 	damage = 125
 	shell_speed = AMMO_SPEED_TIER_6
+	penetration = ARMOR_PENETRATION_TIER_10 + ARMOR_PENETRATION_TIER_5
+
+/datum/ammo/bullet/sniper/anti_materiel/proc/stopping_power_knockback(mob/living/living_mob, obj/projectile/fired_projectile)
+	var/stopping_power = min(CEILING((fired_projectile.damage/30), 1), 5) // This is from bullet damage, and does not take Aimed Shot into account.
+
+	. = stopping_power
+
+	if(!living_mob || living_mob == fired_projectile.firer)
+		return stopping_power
+
+	if(stopping_power > 2)
+
+		// Depending on target size and damage, may apply a mini-stun to interrupt channels. Support your allies!
+		// For reference: Scout Impact stuns for up to 1s and slows for up to 10s, Shotgun stuns for 1.4s and slows for 4s
+		if(living_mob.mob_size >= MOB_SIZE_BIG)
+			// If above 90 damage, screenshake. This maxes out at (2,3), weaker than other impact rounds.
+			if(stopping_power > 3)
+				shake_camera(living_mob, (stopping_power - 3), (stopping_power - 2))
+			if(HAS_TRAIT(living_mob, TRAIT_CHARGING) && isxeno(living_mob))
+				to_chat(living_mob, SPAN_WARNING("A sudden massive impact strikes you, but your charge will not be stopped!"))
+				return stopping_power
+			if(stopping_power >= 4)
+				to_chat(living_mob, SPAN_XENOHIGHDANGER("You are knocked off-balance by the sudden massive impact!"))
+				if(living_mob.mob_size >= MOB_SIZE_IMMOBILE && !((fired_projectile.projectile_flags & PROJECTILE_BULLSEYE) && living_mob == fired_projectile.original)) // Queens and Crushers
+					return stopping_power // For Crushers and Queens, must be aimed at them.
+				living_mob.KnockDown(0.05) // Must deal more than 90 damage to mini-stun big mobs for 0.1s
+				// Can't interrupt a big mob unless it's completely alone with nothing blocking the shot.
+			else
+				to_chat(living_mob, SPAN_XENODANGER("You are shaken by the sudden heavy impact!"))
+		else
+			// If above 60 damage, screenshake. This maxes out at (3,4) like buckshot and heavy rounds. (1,2) (2,3) or (3,4)
+			shake_camera(living_mob, (stopping_power - 2), (stopping_power - 1))
+			if(living_mob.body_position != LYING_DOWN)
+				to_chat(living_mob, SPAN_XENOHIGHDANGER("You are thrown back by the sudden massive force!"))
+				slam_back(living_mob, fired_projectile)
+			else
+				to_chat(living_mob, SPAN_XENODANGER("You are shaken by the sudden heavy impact!"))
+
+			if(isxeno(living_mob))
+				living_mob.KnockDown((stopping_power - 2)*0.05) // Up to 0.3s on a solo target.
+			else
+				if(living_mob.stamina)
+					living_mob.apply_stamina_damage(fired_projectile.ammo.damage, fired_projectile.def_zone, ARMOR_BULLET)
+					// Not sure what this comes out to exactly, but follows the example of other heavy ammo like slugs of applying full base damage as stamina damage.
+				else
+					living_mob.KnockDown((stopping_power - 2)*0.3) // Rare exception of up to 1.8s on non-xenos without stamina.
+
+	return stopping_power
 
 /datum/ammo/bullet/sniper/anti_materiel/on_hit_mob(mob/target_mob,obj/projectile/aimed_projectile)
 
 	var/mob/living/living_target = target_mob
 
+	var/stopping_power = stopping_power_knockback(living_target, aimed_projectile)
+
 	if((aimed_projectile.projectile_flags & PROJECTILE_BULLSEYE) && target_mob == aimed_projectile.original)
 
 		var/amr_counter = 0
@@ -150,22 +200,28 @@
 		var/size_damage_mod = 0.8 // 1.8x vs Non-Xenos (225)
 		var/size_current_health_damage = 0 // % Current Health calculation, only used for Xeno calculations at the moment.
 		var/focused_fire_active = 0 // Whether to try and use focused fire calculations or not, for that kind of target.
+		var/slow_duration = stopping_power // Based on damage dealt.
+
+		if(slow_duration <= 2) // Must be over 60 base damage.
+			slow_duration = 0
 
 		if(isxeno(target_mob))
 			var/mob/living/carbon/xenomorph/target = target_mob
 			size_damage_mod -= 0.2 // Down to 1.6x damage, 200.
 			size_current_health_damage = 0.1 // 1.6x Damage + 10% current health (200 + 10%, 223 vs Runners)
 
-			if(target.mob_size >= MOB_SIZE_XENO && (target.caste_type != XENO_CASTE_DEFENDER))
+			if(target.mob_size >= MOB_SIZE_XENO)
 				size_current_health_damage += 0.1 // 1.6x Damage + 20% current health
 				focused_fire_active = 1 // Focus Fire Required. Only deals 50% bonus damage on a first Aimed Shot, then 75%, then 100%. Resets with a successful aimed shot on another target.
+				slow_duration = max(slow_duration-1, 0)
 
-			if(target.mob_size >= MOB_SIZE_BIG && (target.caste_type != XENO_CASTE_DEFENDER))
+			if(target.mob_size >= MOB_SIZE_BIG)
 				size_damage_mod -= 0.6 // Down to 1x Damage.
 				size_current_health_damage += 0.1 // 1x Damage + 30% current health.
 				focused_fire_active = 1
+				slow_duration = max(slow_duration-1, 0)
 				// Most T3s have around 650 to 700 HP, meaning the health modifier grants a MAXIMUM of around 195-210 damage for a total max of 320-335. This is fully focused (3 shots) and at max HP.
-				// Queen takes around 275 at max health and unfocused, 425 fully focused. Defender only takes 200 damage, even while fortified, but still causes falloff like a Big Xeno.
+				// Queen takes around 275 at max health and unfocused, 425 fully focused.
 				// At low health, does little more than a normal shot. Does WORSE than a normal shot if unfocused and hitting through blockers, all of which stack to reduce it.
 
 			var/final_xeno_damage = ((damage * size_damage_mod) + ((target.health + damage) * size_current_health_damage))
@@ -173,13 +229,21 @@
 			if(focused_fire_active && amr_counter) // If this is a target that needs to be focus-fired and the gun supports it, reduce bonus damage to 50%, then 75%, then 100%
 				// If amr_counter is 0, then the gun likely doesn't have the tracker functions, so skip this and deal normal damage.
 				final_xeno_damage *= (0.25 + (0.25 * amr_counter))
+				slow_duration *= (0.25 + (0.25 * amr_counter)) // 0-3s slow on Big mobs, based on Focus and falloff.
 
 			living_target.apply_armoured_damage((final_xeno_damage), ARMOR_BULLET, BRUTE, null, penetration)
 
 		else
 			living_target.apply_armoured_damage((damage*size_damage_mod), ARMOR_BULLET, BRUTE, null, penetration)
 
-		// Base 1.8x damage to non-xeno targets (225), 1.6x + 10% current against Runners and Defenders (223), 1.6x + 20% current health against most non-Runner xenos, and +30% current health against Big xenos. -Kaga
+		if(slow_duration && (living_target.mob_size != MOB_SIZE_XENO_SMALL) && !(HAS_TRAIT(living_target, TRAIT_CHARGING))) // Runners and Charging Crushers are not slowed.
+			living_target.Slow((slow_duration / 2))
+			if(slow_duration >= 2)
+				living_target.Superslow((slow_duration / 4))
+		if(stopping_power > 3)
+			living_target.Daze(0.1) // Visual cue that you got hit by something HARD.
+
+		// Base 1.8x damage to non-xeno targets (225), 1.6x + 10% current against Runners (223), 1.6x + 20% current health against most non-Runner xenos, and 1x + 30% current health against Big xenos. -Kaga
 		// This applies after pen reductions. After hitting 1 other thing, it deals 80% damage, or 40% after hitting a dense wall or big xeno.
 
 		if((focused_fire_active || isxeno(target_mob)) && !(target_mob.is_dead()))
@@ -253,6 +317,7 @@
 	accuracy = HIT_ACCURACY_TIER_8
 	damage = 150
 	shell_speed = AMMO_SPEED_TIER_6 + AMMO_SPEED_TIER_2
+	penetration = ARMOR_PENETRATION_TIER_10 + ARMOR_PENETRATION_TIER_5
 
 /datum/ammo/bullet/sniper/elite/set_bullet_traits()
 	. = ..()
diff --git a/code/modules/cm_marines/equipment/kit_boxes.dm b/code/modules/cm_marines/equipment/kit_boxes.dm
index c26bafe7123a..ec19cca92033 100644
--- a/code/modules/cm_marines/equipment/kit_boxes.dm
+++ b/code/modules/cm_marines/equipment/kit_boxes.dm
@@ -71,7 +71,7 @@
 
 /obj/item/storage/box/spec/sniper/anti_materiel/fill_preset_inventory()
 	name = "\improper AMR equipment case"
-	desc = "A large case containing an experimental XM43E1, a set of M45 ghillie armor and helmet, a M42 scout sight, ammunition, spotter equipment, and additional pieces of equipment.\nDrag this sprite onto yourself to open it up! NOTE: You cannot put items back inside this case."
+	desc = "A large case containing an experimental XM43E1, a set of M45 ghillie armor and helmet, an M42 scout sight, ammunition, a set of spotter gear, and additional pieces of equipment.\nDrag this sprite onto yourself to open it up! NOTE: You cannot put items back inside this case."
 	new /obj/item/clothing/suit/storage/marine/ghillie(src)
 	new /obj/item/clothing/head/helmet/marine/ghillie(src)
 	new /obj/item/clothing/glasses/night/m42_night_goggles(src)
diff --git a/code/modules/projectiles/guns/specialist/sniper.dm b/code/modules/projectiles/guns/specialist/sniper.dm
index 5b4a81fde273..eb52f9c118b5 100644
--- a/code/modules/projectiles/guns/specialist/sniper.dm
+++ b/code/modules/projectiles/guns/specialist/sniper.dm
@@ -29,7 +29,7 @@
 	. = ..()
 	if(!has_aimed_shot)
 		return
-	. += SPAN_NOTICE("This weapon has an unique ability, Aimed Shot, allowing it to deal great damage after a windup.<br><b> Additionally, the aimed shot can be sped up with a tracking laser, which is enabled by default but may be disabled.</b>")
+	. += SPAN_NOTICE("This weapon has a special ability, Aimed Shot, allowing it to deal increased damage and inflict additional crippling effects after a windup, depending on the ammunition used.<br><b> Additionally, the aimed shot can be sped up with a spotter or by using the tracking laser, which is enabled by default but may be disabled.</b>")
 
 /obj/item/weapon/gun/rifle/sniper/Initialize(mapload, spawn_empty)
 	if(has_aimed_shot)
@@ -362,12 +362,13 @@
 
 /obj/item/weapon/gun/rifle/sniper/XM43E1
 	name = "\improper XM43E1 experimental anti-materiel rifle"
-	desc = "An experimental anti-materiel rifle produced by Armat Systems, recently reacquired from the deep storage of an abandoned prototyping facility. This one in particular is currently undergoing field testing. Chambered in 10x99mm Caseless.\nThis weapon can punch through thin metal plating and walls, though it'll lose most of its lethality in the process. It can even work for demolitions, with experienced users known to disassemble segments of solid, reinforced walls in the field with just a single standard magazine of 10x99mm. In lieu of explosives or an engineer, they instead use each of the 8 shots to break down vital structural supports, taking the wall apart in the process."
+	desc = "An experimental anti-materiel rifle produced by Armat Systems, recently reacquired from the deep storage of an abandoned prototyping facility. This one in particular is currently undergoing field testing. Chambered in 10x99mm Caseless.\n\nThis weapon can punch through thin metal plating and walls, though it'll lose most of its lethality in the process. It can even work for demolitions, with experienced users known to disassemble segments of solid, reinforced walls in the field with just a single standard magazine of 10x99mm. In lieu of explosives or an engineer, they instead use each of the 8 shots to break down vital structural supports, taking the wall apart in the process."
 	icon = 'icons/obj/items/weapons/guns/guns_by_faction/uscm.dmi'
 	icon_state = "xm43e1"
 	item_state = "xm43e1"
 	unacidable = TRUE
 	indestructible = 1
+	aiming_time = 2 SECONDS
 	aimed_shot_cooldown_delay = 4.5 SECONDS
 	var/focused_fire_counter = 0
 	var/datum/weakref/focused_fire_target = null