Part 4: The Battle Joined: Vietnam, the Eaglehorse and the Sheridan

In 1978, my first Platoon Sergeant, SFC Terry Sperry told very few war stories despite two tours in Vietnam. He could go on for hours on tank trivia and the history of the American horse cavalry in the Southwest from the period of 1865-1885 was by far his favorite topic. Ask how the red and white cavalry guidon evolved from the "swallow tail" style to the modern design and stand by for about ten minutes on topic.

Sperry had been both with the Blackhorse and the 25th Infantry in Vietnam, his first tour had been as a Sheridan driver. He told two Vietnam stories that I recall, the Sheridan story went like this:

"Yes, I remember them, I was a driver in 1970 when we got them. Nice new tank that ran well as long as ... you didn't get your ass shot off. In the base camps, we talked about the merits of driving or being in the turret. As the driver, at any given minute, I expected a blinding flash followed by sailing through the air as a mine went off under my ass ... but most of the drivers I knew survived ... for the TC and loader, sitting high in the turret ... well that's where the RPGs always hit and I saw a lot of those guys end up in pretty rough shape ..."

By now the Platoon Room was deathly silent, new troopers listened with eyes the size of silver dollars .... Sperry had his audience just about where he wanted them ...

"But I did see some pretty tough fights, took part in more than my share when I was sure my number was about up ..."

With the constantly lit Marlboro, he was now punctuating the story with jabbing motions with his hands, the ash end resembled a tracer round and the smoke trails and rings ... the smoke in front of the main gun a second after firing.

"you see ... the driver's compartment was built just at the wrong height and just the wrong size ... in eleven months in the ' hole ', I swear to God, if it had two wings, four feet, six legs, or 160 feet, it ended up falling into my lap. I kept a ball peen hammer next to me, wasn't afraid of the VC, I was fighting for my life against bugs, bats, rats and ... CATS!!"

The tension broken, the room would break out into laughter. Sp/4 Bell would say:

"Aww Sarge ... you was just telling a joke!!".

LTC (Ret) Burton S. Boudinot:

"... I asked for the Armor School Sheridan project officer, the Armor and Engineering Board M551 test officer, and the commanding officer of the 73rd Tank Battalion at Fort Bragg, North Carolina, where the M551 was in operational field testing to be brought to Vietnam. The three LTCs arrived in about a week. After a few days of studying the proposal, we told the J3 who was studying the issue for General Creighton Abrams, the Theater Commander, that we thought the M551 was not well suited for Vietnam."

"' Well ' said the J3, think again. General Abrams wanted to know if the M551 would be of ANY use at all in Vietnam. ... I then briefed Abrams, with these recommendations: The Shillelagh missile system and its components should stay home, and only 27 vehicles should be brought into the country, all with added armor enhancements and especially added belly armor."

"General Abrams said, ' Let's do it! ' ... in January of 1969 the first Sheridans and the new equipment training team arrived in Vietnam. The reception of the 11th ACR was cool but then on January 29, two Sheridans were on picket duty along the Long Binh highway. At about 0230, the crewmen were alerted to movement to their front. The Sheridan searchlights were turned on and enemy troops spotted crossing a dirt road. Two 152 mm ' Bee Hive ' antipersonnel rounds were fired. The next day, over 125 bodies were found."

As the vehicles deployed to Vietnam, at Fort Knox, the Armor School geared up.

Fort Knox Training

Doug Kibbey, Troop G:

"For myself, and others, the first sight close-up of M551 in 'regulation uniform' was to be in AIT at Fort Knox on the Patton series of MBTs when Sheridans of the 1st Training Brigade would appear in the tank parks and on the range roads. The first impression was usually one of keen interest bordering on awe, because of the vehicle's exotic geometry and compact size for such an obviously large weapon. 'What is THAT?' was a question frequently asked."

"A lot of young tankers-in-training were soon to find out, including this one. In the summer of 1971, approximately 33% of the 8 week Armor Crewman AIT class was selected to report to D/1/1 for M551 training, with the entire class already knowing its first duty assignment following that 4-week course. Roughly 50% were to be assigned to Vietnam (including this contributor) and the remainder to Germany, with a very few possibly to Korea."

"I was assigned to D/1/1 Training Company which was housed in some of the last open bay wooden barracks from the WWII era. The vehicles were equipped with the Closed Breech Scavenging System without bore evacuators and were fully Shillelagh missile capable. Considerable time was given over to procedures relating to this system. One missile was fired in demo, all missile 'firing' training was performed on a turret trainer/simulator. The vehicles were fitted out as standard with no accessory gun shields or mine plates. This training course was to be the only time that most Sheridan crewman would ever see the smoke grenade launchers actually fired and two exposures of this event are provided."

Col (Ret) Clint Ancker, Troop G:

"I attended Armor Officer Basic Course in late summer of 1970. The course was nine weeks long. There was little or nothing on the Sheridan until quite late when someone decided that we desperately needed to actually shoot them before we graduated. As the course was already set, it was decided to that we would shoot the Sheridan on Saturday, after graduation. This was a very unpopular decision, but there was nothing we could do about it. Many of my classmates had already made plans to leave either Friday after graduation or on Saturday, but these plans were now on hold."

"Saturday morning we all gathered at one of the ranges at Fort Knox for our familiarization shoot. Many of my classmates drove their cars to the range in order to make a quick departure. The firing itself was almost anticlimactic. Each of us was to TC a Sheridan and fire a round or two, for familiarization. This all went off without a hitch, except for one of my classmates who failed to heed the warning that the Sheridan main gun round produced prodigious recoil. He did not hold on to the TC's station firmly when the gun fired and ended up with a mouth full of M2 .50 caliber machine gun. This was not the last I was to run into problems generated by the recoil of the M551."

Vietnam

SFC (Ret) Tony Perez, Troop E:

"I was a TC and one thing I remember was that most of the time we fired the main gun, it was more like duck hunting than tank gunnery. I seldom recall the gunner at his position in the turret, we would load and I'd lay the gun and just about estimate the elevation. Because of the terrain and heavy growth, anything beyond 500 meters seemed a very long way to shoot. We believed that if we were standing in our open hatches and there was any sort of explosion, you stood a chance of surviving by being thrown clear of the tank. So, another reason for the loader / gunner to load the main gun and get to the loaders hatch. And, he had an M60 machine gun up there and the more people looking from the turret, the better the chance to see and shoot first. Like most everyone else, I had the TC's control rigged with an extension so I could comfortably be on the TC's stand and be able to slew the turret and fire the gun quickly."

"The worst day I had without getting shot at was breaking down in a really thick jungle and listening as the rest of the platoon maneuvered away from me in a sweep. They said the XO would be along really quick in the maintenance PC and they'd stay with me until the recovery vehicle would drag me out. So, everyone was up on in the turret and we couldn't see more than fifteen feet in any direction. I think we waited about an hour and I could hear the Troop motors driving away and it is a very big jungle and a very small Sheridan."

Col (Ret) Clint Ancker, Troop G:

"I joined 2nd Squadron, 11th Armored Cavalry Regiment in September, 1971. When I arrived, 2nd Squadron was the only element of the 11th ACR still in Vietnam. The squadron consisted of three ground cavalry troops (E, F, and G), the squadron howitzer battery, and what had been the Regimental Air Cavalry Troop. The squadron did not have its normal organic tank company. I was assigned as platoon leader, 3rd platoon, G Troop and flown out to Fire Support Base Andrews to link up with my platoon. The platoon consisted of 10 vehicles. There were seven M113A1 armored cavalry assault vehicles (ACAV). Four were standard configuration with an M2 at the commander's station and two M-60 machineguns with a gun shield, mounted on either side of the cargo hatch. Two had a 40mm automatic grenade launcher in place of the M2 and one had an 81mm mortar in the cargo compartment (this was a M125A1). The mortar track also had a rear facing M-60 MG."

"I also had three M551 Sheridan Armored Reconnaissance/Airborne Assault Vehicles. Normally the Sheridan was configured with a 152mm main gun, an M73 7.62mm coaxial machinegun, and an M2 Browning .50 caliber machinegun at the TC's station. All of the Sheridans in the troop, and I assumed in the squadron, were configured with a second M2 .50 cal at the loader's station. One of my Sheridans was also configured with an M-60 MG at the driver's station. Each Sheridan also had a mine plate on its belly. The mine plate was a Vietnam addition and consisted of a roughly one inch steel plate that covered the whole bottom of the chassis. This added significant weight to the vehicle, but provided a significant improvement in survivability from mine hits."

"While capable of firing the shillelagh missile, none of the Sheridans carried any shillelaghs. For the main gun they carried canister rounds and HEAT MP rounds. Most of the basic load was canister rounds. These rounds had projectiles that looked like a coffee can. They had a flat nose with no fuze. They contained thousands of flechettes, small nail like darts. Each had a pointed nose and small fins, like an arrow, swaged out of the body of the flechette. When fired, the front and sides of the round fell away and the flechettes spread out like a shotgun round. The base of the round fell to the ground and when lying on the ground could not be distinguished from a dud HEAT round that was buried in the ground."

"The best part of the Sheridan was its suspension. It could go places that the ACAV couldn't. It had a very low ground pressure, was very rugged, and almost never threw track. While the M113 threw track not infrequently, the Sheridan rarely threw track. I only saw one thrown track on a Sheridan in Vietnam. This happened in an old trench line where the Sheridan slipped into one of the trenches and threw a track to the inside."

"At one point while I was the platoon leader, we shifted areas of operations. The new AO allowed recon by fire without any clearances. The first day we were allowed to do this, I told my Sheridans to load HEAT-MP for the recon by fire. SSG Bruce Thorton, commander of G-38 gave me an up (meaning he had a firing light) just prior to "open fire". When told to "open fire" everyone opened up. G-38 fired its HEAT round and SSG Thorton simply disappeared down the TCs hatch. After the "cease fire" someone keyed the platoon net, and after about five seconds, SSG Thorton's voice came over the net and he said "Why didn't someone warn me?" After the operation that day, I talked to him and he said that it was the first time he'd ever fired a HEAT round. The canister round was a very low pressure, low velocity round with almost no recoil. The HEAT round was a full pressure, relatively high velocity (relative, because the 152 gun system was actually a low velocity cannon compared to the tank main gun on an M-48 or M-60) round with ferocious recoil. A 152mm round on a 17 ton chassis, caused the Sheridan to come up off the first two roadwheels. Unless the TC braced himself, the recoil would bang him around significantly."

Doug Kibbey, Troop G:

"The Sheridan's utility was to be tested under fire in Vietnam, pending resolution of SOME of the problems relating to the hazards of the combustible case ammunition for the M81 gun. Sheridans in Vietnam service were usually assigned to light armored cavalry units alongside M113 ACAVs, usually in smaller numbers. In 2/11th ACR, the ratio was approximately 1 M551: 3 M113s. Like most armored vehicles in extended combat operations, they were heavily overloaded and being heavier and more heavily armed than the M113's, one usually led any column in breaking bush. This led to the most frequent mechanical difficulty with the vehicle, overheating."

"Modifications were numerous, apart from the addition of a variety of gun shields and the mine plate kit, the most frequent involved the extension of the exhaust stack with a metal artillery munitions tube (to raise the exhaust plume away from the crew in heavy bush), the addition of an M60 or M2 machine gun at the loaders hatch, an additional stowage rack welded to the rear deck, and frequently the relocation of the commanders' turret control handle to a position virtually outside the turret in the TC's cupola. Given the threat of mines and RPGs, crews of M551s and M113s tended to ride outside of the vehicle with no one inside except the driver, who often reinforced his position with sandbags inside and/or out. Few M551s in Vietnam retained a full compliment of swim gear, which fell victim to the rigors of busting bush and was subsequently cannibalized as tenting or construction material. The only contribution of the side mounted floatation pods was to possibly attenuate the effects of shaped-charge weapons and other fire."

"On patrol, the TC generally acted as his own gunner with the relocated remote turret control handle, typically "firing from the hip". The round most often chambered was the 'canister' round containing ~10,000 flechettes (darts) usually just referred to as "nails", which is what they amounted to. HEP rounds were also carried in the event a bunker or hardened position was encountered. At best, the main gun was bore-sighted, as tank v. tank engagements did not occur."

"I was among the members of G Troop, 2/11th ACR when the squadron stood down in March-April 1972. The vehicles were driven to Long Binh depot and prepared for shipment (the M551s) to the United States, or hand-over to the ARVN (the M113s)."

LTC ( Ret) Lee Allen:

"While with the second squadron in Vietnam, I had the opportunity to see a couple of Sheridans hit by RPGs. Once the combustible casings caught fire, which was almost instantaneously if they were hit, the whole vehicle exploded and burned. Because of the aluminum hull, the end result was a big puddle of molten metal on the ground and the loss of the entire crew."

"The firing system was what seemed like an endless series of electromechanical switches any one of which could shut down the whole system. It was a terribly frustrating thing to have to trouble shoot the system to locate some mechanism breaking the circuit. This was especially true in Vietnam where the heat and humidity raised havoc with the temperamental system. The ever ingenious troopers solved the problem, if you can believe it, by running a piece of WD-1, commo wire, from the electrical firing mechanism (firing pin, you might call it) to the overhead dome light. When the tank commander gave the word to fire, the loader would reach up and turn the dome light on. It worked."

The Sheridan was fielded to most of the cavalry squadrons in Vietnam over a two year period. Almost as soon as the fielding was complete, the withdrawal of US forces was well underway. It did offer commanders a vehicle that could accompany the M113s where the M48s could not follow. The bee-hive round on occasion, could yield dramatic results. Like much of Vietnam, it was all done with the best intentions. The Sheridan was an answer in search of a question.

Many of the problems discovered in this harsh environment would continue, only partially solved, for the life of the system as a combat vehicle. Even without the laser range finder and missile components, the turret was prone to electrical problems. The CBSS fixed some of the cannon problems related to clearing the tube immediately after firing but the complicated and touchy breech block, that to work correctly would unscrew, swing and pivot, never was fully trustworthy. The combustible case ammunition was ill suited to the humidity in Vietnam, the rubber "baggy" that held the propellant and was a part of the round would easily tear and spill. The mechanical problems, overheating and chronic belt and pulley failures were eventually solved.

"I was in the room in the Pentagon, in the summer of 1977, when the decision was made to phase out both the Sheridans (except for the 82^nd Airborne) and the M60A2s.  I was pulling slides in the behind-the-screen projection room for BG Lou Wagner as he was briefing the Chief of Staff (Shy Meyer), The TRADOC Commander (Donn Starry), the AMC Commander (John Guthrie) and other luminaries. We were briefing the results of our study which was to determine how many M1s to build and distribute.  Part of the question was what we were going to do with the Sheridans and the M60A2s and when were we going to do it.  Our briefing was very flexible: while I was putting slides on the viewgraph, Tom White (later RCO and SecArmy) was busy preparing the next slide. We were hard pressed to stay one step ahead of BG Wagner, but, we managed. Tom’s pre-West Point experience in graphical arts truly paid off."
 

"The first part of the briefing went well, but then the question about what to do with the Sheridans came up. Then things began to get hot.  Actually, from Tom’s and my perspective, that’s when things became fun.  The briefing stopped as General Starry began to explain all the problems with the Sheridan.  At this point, General Guthrie got a little defensive and began to defend the Sheridan program from the AMC perspective.  Of course Starry had just left command of V Corps, he had been the Chief of Armor, he had been the Blackhorse Commander in Vietnam, and he was at that time, THE Army’s expert on armor and armor operations.  His focus in 1977 was Europe, he knew the GDP, and he knew how many targets the Regiments would have to 'service'  in the now quaint lexicon of AirLandBatttle — which he later developed as the TRADOC Commander.  In short, it was no contest; although I thought (hoped) Gen Starry was getting ready to leap across the table and take on the AMC commander.  Starry gave his usual eloquent, though impassioned, rationale for getting rid of the M81 (is that right?) gun/missile system in whatever vehicular variation.  Gen Meyer agreed and the Army got rid of both the Sheridan and M60A2 with all deliberate speed."
 

"One Sheridan anecdote: As you may recall,  when parked, the Sheridan gun tube was directed over the left sponson and depressed.  LTG Sid Berry, the V Corps Commander came to visit us in the spring of 1978.  This was also during the time when our wearing of the black beret was becoming an Army-wide issue. I was leading him through the area as he inspected the Squadron and as we made our way through the tricky footing of one of the Cav Troop’s motor pool, he hopped over a curb, banged into a gun barrel and planted the three stars on his hat into his forehead.  As we walked back to the Squadron aid station, I couldn’t help but point out that one of the reasons the beret was advantageous around armored vehicles was that it didn’t have a bill to block your vision.  A great point, I thought, but perhaps lost on the Corps Commander in his pain and embarrassment."