EXP Undertow Gen. 2 attachment in MW4

MuzzleHeavy Silencer

The EXP Undertow Gen. 2 is a muzzle attachment (“Heavy Silencer”) that community sites list for 4 weapons: Patriot XMR, Cronen Squall, MAR-9, and Oris 8.6. CODMunity lists a stat change on 4 of them; the largest is damage range +18% on the Cronen Squall (better). It is in 9 popular builds that CODMunity lists.

Community-reportedDMZ Radar, wzranked, ggranked, and CODMunity, read October 28, 2026. Unverified, not Activision data.

Weapons that can equip the EXP Undertow Gen. 2

Activision publishes no compatibility list; 4 community sources report these 4 weapons. No weapon level is reported.

Weapons that can equip the EXP Undertow Gen. 2, with weapon level and the stats the source lists a change for
Weapon	Class	Weapon level	Stats with a listed change
Patriot XMR	Assault Rifle	not reported	bullet velocity (large, better), damage range (large, better), ADS idle sway (large, worse), ADS gun bob (large, worse), ADS speed (moderate, worse), ADS out speed (moderate, worse), vertical recoil (small, better), and horizontal recoil (small, better), and 7 more
Cronen Squall	Assault Rifle	not reported	damage range (large, better), bullet velocity (large, better), ADS idle sway (large, worse), ADS gun bob (large, worse), ADS speed (moderate, worse), ADS out speed (moderate, worse), vertical recoil (small, better), and horizontal recoil (small, better), and 7 more
MAR-9	Marksman Rifle	not reported	bullet velocity (large, better), ADS idle sway (large, worse), ADS gun bob (large, worse), damage range (moderate, better), ADS speed (moderate, worse), ADS out speed (moderate, worse), vertical recoil (small, better), and horizontal recoil (small, better), and 7 more
Oris 8.6	Marksman Rifle	not reported	bullet velocity (large, better), damage range (large, better), ADS idle sway (large, worse), ADS gun bob (large, worse), ADS speed (moderate, worse), ADS out speed (moderate, worse), vertical recoil (small, better), and horizontal recoil (small, better), and 7 more

What the EXP Undertow Gen. 2 changes

Percent changes are relative to the base value with nothing attached (CODMunity, read November 4, 2026).

Key stats the EXP Undertow Gen. 2 changes on each weapon, from the base value with nothing attached
Weapon	Stat	Base	With it	Change
Patriot XMR	Bullet velocity	620 m/s	719 m/s	+16% (better)
	Damage range	100%	116%	+16% (better)
	ADS speed	280 ms	311 ms	+11% (worse)
	Vertical recoil	52.6	49.4	−6% (better)
	Horizontal recoil	14.4	13.5	−6% (better)
	Movement speed	4.54 m/s	4.45 m/s	−2% (worse)
	ADS movement speed	2.22 m/s	2.18 m/s	−2% (worse)
Cronen Squall	Damage range	100%	118%	+18% (better)
	Bullet velocity	660 m/s	766 m/s	+16% (better)
	ADS speed	305 ms	336 ms	+10% (worse)
	Vertical recoil	50.4	47.4	−6% (better)
	Horizontal recoil	6.3	5.9	−6% (better)
	Movement speed	4.55 m/s	4.46 m/s	−2% (worse)
	ADS movement speed	2.24 m/s	2.20 m/s	−2% (worse)
MAR-9	Bullet velocity	670 m/s	777 m/s	+16% (better)
	Damage range	100%	114%	+14% (better)
	ADS speed	330 ms	360 ms	+9% (worse)
	Vertical recoil	62.0	58.3	−6% (better)
	Horizontal recoil	14.9	14.0	−6% (better)
	Movement speed	4.41 m/s	4.32 m/s	−2% (worse)
	ADS movement speed	2.10 m/s	2.06 m/s	−2% (worse)
Oris 8.6	Bullet velocity	570 m/s	661 m/s	+16% (better)
	Damage range	100%	116%	+16% (better)
	ADS speed	260 ms	291 ms	+12% (worse)
	Vertical recoil	52.0	48.9	−6% (better)
	Horizontal recoil	30.0	28.2	−6% (better)
	Movement speed	4.77 m/s	4.67 m/s	−2% (worse)
	ADS movement speed	2.78 m/s	2.72 m/s	−2% (worse)

Smaller changes are left out of the table: 8 other stats on the Patriot XMR, 8 other stats on the Cronen Squall, 8 other stats on the MAR-9, and 8 other stats on the Oris 8.6.

Changes across weapons

The stats it changes on 4 weapons, with the lowest and highest change.

Range of the EXP Undertow Gen. 2's reported changes per stat across weapons
Stat	Weapons	Lowest change	Highest change	Verdicts
Damage range	4	+14%	+18%	4 better, 0 worse
Bullet velocity	4	+16%	+16%	4 better, 0 worse
ADS speed	4	+9%	+12%	0 better, 4 worse
Horizontal recoil	4	−6%	−6%	4 better, 0 worse
Vertical recoil	4	−6%	−6%	4 better, 0 worse
ADS movement speed	4	−2%	−2%	0 better, 4 worse
Movement speed	4	−2%	−2%	0 better, 4 worse
ADS gun bob	4	+15%	+15%	0 better, 4 worse
ADS idle sway	4	+15%	+15%	0 better, 4 worse
ADS out speed	4	+8%	+9%	0 better, 4 worse
Horizontal gun kick	4	−6%	−6%	4 better, 0 worse
Vertical gun kick	4	−6%	−6%	4 better, 0 worse
Crouch movement speed	4	−2%	−2%	0 better, 4 worse
Firing movement speed	4	−2%	−2%	0 better, 4 worse
Strafe speed	4	−2%	−2%	0 better, 4 worse

How it ranks among muzzle attachments

Its largest change on each weapon, compared with the other muzzle attachments the source lists that stat for.

Patriot XMR: its large bullet velocity change (better) is the only one listed.
Cronen Squall: its large damage range change (better) is the weakest of 2 muzzle attachments.
MAR-9: its large bullet velocity change (better) is the only one listed.
Oris 8.6: its large bullet velocity change (better) is the only one listed.

Pros and cons the sources list

None reported, which is different from having none.

Popular builds that use the EXP Undertow Gen. 2

CODMunity lists 9 popular builds that use it: 3 for Multiplayer and 6 for DMZ. The styles are Versatile, Mobility, Long Range, and Apex Attachment. The same builds also use optic, barrel, rear grip, laser, magazine, and underbarrel attachments.

Popular builds that use the EXP Undertow Gen. 2
Weapon	Mode and style	Tier	Other attachments	Builder
Oris 8.6	Multiplayer, Versatile with Apex Attachment	Contender	Optic: Cronen R808, Barrel: EXP Crosstac 22", Rear Grip: Bruen R7-TC Grip, and Laser: XRK Clutch-LS	Open in the builder: Oris 8.6, Versatile
Cronen Squall	Multiplayer, Versatile with Apex Attachment	Very good	Optic: ZLR Type C, Magazine: 30 Round Mag, and Rear Grip: Cronen SQL Grip	Open in the builder: Cronen Squall, Versatile
Cronen Squall	Multiplayer, Mobility	Very good	Optic: ZLR Type C, Magazine: 60 Round Drum, and Laser: SZ Gen.6 PEQ	Open in the builder: Cronen Squall, Mobility
Patriot XMR	DMZ, Long Range	Not tiered	Optic: KV Corsac Holo, Barrel: EXP Raid Tac 18.5", Underbarrel: FSS Fireline Grip, and Magazine: 50 Round Drum Mag	Open in the builder: Patriot XMR, Long Range
Patriot XMR	DMZ, Apex Attachment with Apex Attachment	Not tiered	Optic: KV Corsac Holo, Underbarrel: FSS Fireline Grip, Magazine: 50 Round Drum Mag, and Rear Grip: Schlager ATTACK-7 Grip	Open in the builder: Patriot XMR, Apex Attachment
Oris 8.6	DMZ, Long Range with Apex Attachment	Not tiered	Optic: Cronen R808, Barrel: EXP Crosstac 22", Magazine: 20 Round Mag, and Rear Grip: Bruen R7-TC Grip	Open in the builder: Oris 8.6, Long Range
Cronen Squall	DMZ, Long Range with Apex Attachment	Not tiered	Optic: KV Corsac Holo, Barrel: FJX Sypher 27", and Magazine: 60 Round Drum	Open in the builder: Cronen Squall, Long Range
MAR-9	DMZ, Long Range with Apex Attachment	Not tiered	Optic: KV Corsac Holo, Magazine: 30 Round Mag, Rear Grip: Schlager PLM-S9, and Laser: SZ Gen.6 PEQ	Open in the builder: MAR-9, Long Range
MAR-9	DMZ, Long Range	Not tiered	Optic: KV Corsac Holo, Barrel: LM Class 6 HBL, Magazine: 30 Round Mag, and Rear Grip: Schlager PLM-S9	Open in the builder: MAR-9, Long Range

Builds are community-reported and unverified.

Frequently asked questions

What does the EXP Undertow Gen. 2 do in MW4?

CODMunity lists 60 stat changes for it across 4 weapons: 24 better and 36 worse. The largest is damage range +18% on the Cronen Squall (better).

Which weapons can use the EXP Undertow Gen. 2?

Community sites list Patriot XMR, Cronen Squall, MAR-9, and Oris 8.6. Activision has not published a compatibility list.

Is the EXP Undertow Gen. 2 in a popular build?

Yes. CODMunity lists it in 9 popular builds, on Oris 8.6, Cronen Squall, Patriot XMR, and MAR-9.

Sources: DMZ Radar (read October 24, 2026); wzranked (read October 24, 2026); ggranked (read October 28, 2026); CODMunity (read October 28, 2026). Updated November 4, 2026.