This is the massive cannon US Marines are using to obliterate ISIS fighters in Syria

Spc. Jacquelynn Gaines/US ArmyUS Army soldiers prepare to fire an M-777 Howitzer during Anakonda 2016.

As coalition forces slowly make gains in liberating Mosul from ISIS control, another campaign to finally oust the terror group’s forces is taking place in Raqqa, Syria.

According to The Washington Post, a contingent of US Marines from the 1st Battalion, 4th Marine regiment recently established a combat outpost in Syria to assist local US-backed forces, who have begun their assault on the city.

By providing support through various means, Coalition troops have reportedly killed hundreds of enemy fighters and destroyed more than 200 fortifications. Coalition forces have also claimed that they have conducted more than 300 airstrikes around Raqqa in the past month alone.

One of the ways in which the Marines have pounded their enemies is with the fearsome M-777 Howitzer. Firing 155-millimetre shells, these cannons can have a range up to 25 miles with special GPS-guided munitions.

Here’s a look at the deadly weapon that the Marines are hitting ISIS with.

Raqqa has been a relative safe haven for ISIS militants since 2014, but it might be changing soon. Under the cover of darkness, Syrian Democratic Forces, with the assistance of US Marines, hit the Tabqah Dam on Tuesday. The dam, about 25 miles from Raqqa, has been used as ISIS' headquarters since 2013.

Google Maps

Source: Operation Inherent Resolve, Rudaw

In years past, Coalition forces were reportedly unable to outright bomb the ISIS-controlled dam with airstrikes, due to the possibility of flooding. With the Coalition's conventional ground assault well underway, things are looking different now.

Screenshot via Google Maps

Source: Operation Inherent Resolve, Mirror

The M-777 Howitzer, just one of the tools in the Marine Corps' arsenal, was staged within striking distance of the self-proclaimed ISIS capital of Syria, in order to assist with this assault.

Staff Sgt. Danielle Bacon/US Marine Corps

US Marines with Battalion Landing Team 3/8, 26th Marine Expeditionary Unit move a M-777 Lightweight Howitzer into place on the flight deck of USS Carter Hall at the Morehead City Port, NC, August 28, 2010.

Source: The Washington Post

Once the dam is free of ISIS control, it will isolate Raqqa from three sides, giving Syrian troops the strategic advantage to further liberate areas of the city. According to The Post, an unknown number of Marines with 1st Battalion 4th Marine Regiment have set up their cannons for support.

Lance Cpl. Sullivan Laramie/US Marine Corps

US Marines from the 10th Marine Regiment fire an M-777 Howitzer during Rolling Thunder, a biannual training exercise at Fort Bragg, North Carolina.

Source: The Washington Post

With these guns, Marines can pound ISIS positions, vehicles, and even hardened bunkers with accurate and continuous fire -- a cheaper and a more controlled option compared to an airstrike.

Spc. Evan D. Marcy/US Army

Soldiers with the 82nd Airborne Division fire 155mm rounds using an M-777 Howitzer on Forward Operating Base Bostick, Afghanistan. The Soldiers were registering targets so they would have a more accurate and faster response time while providing fire support.

In 2005, the Marine Corps began fielding the M-777, which was 9,000 pounds lighter than its predecessor: the M-198 Howitzer.

Lt. Col. Daniel F. Bohmer/US Army

US Army soldiers from the 2nd Infantry Division fire an M-777 Howitzer at Forward Operating Base Al Masaak, southern Afghanistan.

Source: US Marine Corps

The M-777 can be dropped, loaded, and ready to fire in under three minutes with a crew of five Marines.

Cpl. Robert Medina/US Marine Corps

US Marines reposition their M-777 Howitzer in Al-Taqaddum, Iraq.

Source: US Marine Corps

The M-777 has proven to be a dependable medium-force weapon for the Marine Corps and US Army, with over 40,000 rounds fired in all sorts of terrain and conditions.

Staff Sgt. Kimberly Bratic/Michigan National Guard

A US Army soldier fires a 155mm round from an M-777 Howitzer during cold weather operations at Camp Grayling Joint Manoeuvre Training Center, Michigan.

Source: BAE Systems

The gun is capable of sustaining a rate of fire of two rounds per minute, however, it can also fire an intense barrage of up to 10 rounds in two minutes.

DoD

Soldiers from Battery A, 2nd Battalion, 3rd Field Artillery Regiment, fire a M-777 Howitzer during a joint operation with A-10 Warthog Thunderbolt II aircraft for Operation Hustler Trough at Fort Bliss, Texas.

Source: BAE Systems

It can fire up to 18.6 miles out with normal munitions. And with Raytheon's Excalibur rounds, it's able to accurately hit targets up to 25 miles away.

Sgt. Sarah Anderson/US Marine Corps

Australian soldiers fire a M-777 Howitzer in support of US Marines on August 11, 2016 at Bradshaw Field Training Area, Northern Territory, Australia.

Source: Military.com

Artillerymen can use high-explosive rounds to suppress the enemy, and smoke rounds to screen friendly movement ...

Sgt. Sarah Anderson/US Marine Corps

An Australian soldier checks rounds before loading an M-777 Howitzer prior to a fire mission in support of US Marines at Bradshaw Field Training Area, Northern Territory, Australia, August 11, 2016. The soldiers and Marines are taking part in Exercise Koolendong 16, a trilateral exercise between the Australian Defence Force, US Marine Corps, and French Armed Forces New Caledonia.

Source: Military Times

... Or illumination rounds to help light up certain areas for night operations.

Staff Sergeant Justin Weaver/US Air Force

US Army Capt. Andrew Fleagle observes illumination rounds fired during Operation Tora Arwa V in Kandahar Provine, Afghanistan.

Artillerymen typically name their guns, though soldiers and Marines receive commands to fire by their gun number -- based on where they are on the firing line.

Staff Sgt. Scott McAdam/US Marine Corps

US Marine Corps Lance Cpl. Justin Miljan, a field artilleryman with Battery A, Battalion Landing Team 1st Bn., 4th Marines, 11th Marine Expeditionary Unit, inspects the breach of his M-777 Howitzer, aptly named the 'Americannon,' during Exercise Alligator Dagger, Dec. 14, 2016.

And when the mission is all over, Marines and soldiers can airlift the M-777 with the MV-22 Osprey, the CH-53E Super Stallion, and the CH-47 Chinook.

Staff Sgt. Kimberly Bratic/Michigan National Guard

US Army soldiers retreat from a CH-47 Chinook after slingloading an M-777 Howitzer during cold weather operations at Camp Grayling Joint Manoeuvre Training Center, Michigan. The air temperature was 30 degrees below zero, winds under the rotor blades were 140 miles per hour, and the wind chill under the helicopter reached -90 degrees.

Source: US Marine Corps

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