I dunno some of these stories are hardly harmless pranks, in which someone got caught being human. Any "prank" that results in someone injured or wanting to "kill" isn't funny to me.

As to the M551 Sheridan Airborne Armored Reconnaissance Vehicle (AARV) it was designed to be air landed and amphibious, into areas where tanks could not be quickly deployed to provide anti-armor capability. The Army therefore did not classify the M551 as a tank, but because it looked so much like a tank it is usually referred to as a tank.

Because the M551 was the standard reconnaissance "tank" of the cavalry it was deployed to Viet Nam in that role. Viet Nam was not "Tank Country" and the armor battalions that were deployed and equipped with the M48A2 90mm gun tank operated in those few areas that were suitable to use of tanks. Even cavalry units operated M48s rather than M551s where tanks could be operated.

The M551 deployed to Viet Nam had a number of problems including severe deterioration of the electrical system in the humid environment. Two or three conventional rounds were supplied to the Cavalry units that used the Sheridan in VN. Probably the most useful was a round that was known as a "Beehive." This type round was also supplied in 90mm and 105mm to tank and artillery crews for anti-personnel use. The Beehive round contained a large number of small flechettes that when fired acted with a shotgun effect. The missile launching capability was not required in VN because of the lack of enemy armor suitable to attack by the Shillelagh missile.

Sheridan suffered a number of problems and the leakage of recoil fluid that destroyed the sophisticated electrical wiring was one of them. It frequently occurred that when the 152mm gun-launcher was fired with a conventional round, especially straight over the center of the hull, the recoil would break the torsion bars in the track suspension system. In training conventional ammunition was fired over the front fender which reduced the strain on the suspension. The recoil of the entire track when conventional ammunition was fired was astonshing to see and uncomfortable to experience. The hull was aluminum armor to reduce the weight of the vehicle to provide amphibious capability. The "armor" was reasonably effective against shrapnel but easily penetrated by direct hit from most all types of hostile fire. For the most part the Sheridan was unsuccessful in "swimming." As to the air landing role the Sheridan had to be stripped of everything removable to lighten it enough to be air landed. It could not be dropped by parachute but had to be landed on a pallet in a low level pass. Even this technique often put too much stress on the suspension system and torsion bars were broken.

When I attended the Armor Officer Basic Course in 1975 we trained on the Sheridan. I vividly recall how just about every instructor that we trained with started their lecture by saying something like, "This is the M-551 Sheridan, that is air deliverable...once!" Meaning that the material condition of one air landed was such that there was no point doing it twice. The instructors also shared that the Sheridan was going to be soon phased out of the inventory, but we trained on them as they were still authorized to cavalry units, and it was said that the Armor Battalion of the 82nd Airborne Division was going to have them for awhile.

When we went to the range for live firing a Shillelagh missile was demonstration launched, but we only fired conventional ammunition. In my "crew" I always got stuck as the loader in the first rotation, I suppose because no one wanted to handle high explosive first. The solid propellant was molded to the projectile and protected by a rubber shroud. The technique of loading was to start the projectile in the breech, take hold of the front edge of the rubber shroud with the left hand and using the fist of the right hand push the projectile into the breech, while peeling back the shroud over the right arm. I still have the rubber shroud from the first round I loaded in this way.

During our field training as cavalry we had Sheridans and M114 ARVs that were also soon to be phased out of the Army. I recall that we had just completed our training and we were leaving the training area. As we passed another Sheridan that was sitting in the middle of a clearing there was three loud pops that sounded like a large caliber gun fired in rapid succession, that was the left front three torsion bars of the other Sheridan breaking. (I took a photograph of this Sheridan as we were passing that probably pissed off the crew even more so I guess that was a sort of "prank.") Apparently the first torsion bar broke and the extra weight transferred to two others caused them to break in turn. In case you are uninformed you cannot operate a Sheridan on broken torsion bars...that's a dead lined vehicle and it's time to call the maintenance team for a recovery. (A torsion bar is about 1 1/2 thick on a Sheridan and provides the "spring" that is constantly pushing the road wheels down. The bar runs across the width of the hull and is secured in the opposite side of the hull from the road wheel it is attached to and is constantly being twisted by the weight and movement of the vehicle over uneven ground. When the torsion bar is broken the road wheel collapses and does not provide any suspension to the vehicle.)

The last time I saw Sheridans around 1990 they were being used by the OPFOR at Ft. Irwin. The hull and turret had been cosmetically altered to resemble Soviet armor and the only functional part of the Sheridans was the automotive and suspension systems. As I recall at that time the only operational Sheridans were those used by the organic armor battalion of the 82nd Airborne Division.

When I reported to the 54th MP Company at Ft. Ord out of AIT I was of course unassigned to a shift and therefore a barracks. The day I arrived I was told to find a bunk in the barracks used by the Company headquarters personnel. Sometime during the night they arranged a wellcome prank when they all jumped out of their bunks yelling "Fire" and ran out of the barracks. I have to say I was not taken in by this although I did get out of my bunk to see what was going on, but did not run out of the barracks with the pranksters. They came back into the barracks with various looks on their faces that indicted they were not pleased that I had not taken the bait. However when I think on it it was a good prank considering the reality of how fast those WWII wood barracks would burn and I'm glad it was only a misfired prank.

There is a tradition of a sort of prank that has been going around the U.S. Army for probably as long as there has been an Army. The story, with many variations of time and place, goes that Pvt. Flynn refused all duty and spent his days sitting out on the parade ground with an empty bucket and a fishing pole. Finally came the day the Army had enough of Flynn and he was discharged the Army. As he went out the gate with discharge in hand one of the sentinals asked Flynn if he ever caught anything in his bucket. Flynn held up his discharge and said, "I sure did."

At the Correctional Facility (stockade) at Ft. Ord I was often assigned to the front gate desk. We had a Sergeant First Class in charge of Correctional Supervision, meaning the stockade turnkeys, that was a real "lifer." One day it happened that I became aware that a guy that worked in the front office of the facility that was not a guard, was sitting at the interior guard desk. I saw the SFC going through my post and proceed through into the custody area. I mentally worked out the time it would take the SFC to get to the interior desk and called the desk. This same guy that didn't belong there answered the phone and I told him the the SFC was headed his way. I didn't hear until much later that he had said "Sergeant M___ is coming......!" and before he could finish his sentence the SFC was standing at the desk. I still get a chuckle thinking about it, I only wish I had been there to see the prank come off.

The story goes that in the days when the U.S. Navy had a large number of destroyers and cruisers with four smoke stacks that it was fun to ask a recruit sailor which of the two stacks were farthest apart. As it happened on the destroyers the spacing of the stacks the first and second stacks were the same distance as the third and forth stacks, with a little more space between the second and third stacks. The rookie sailor would almost enevitably try to figure out if the space between one and two or the space between three and four was greater. The answer is obvious but apparently many gullible recruits spent alot of time trying to figure it out.