Tank Gunnery 1976, Part 7, Final Engagement HEP-T at 2000 Meters

 HEP High Explosive Plastic, muzzle velocity 2,450 fps.  

In this night-fire picture, the flat trajectory of APDS is very clear.  

HEP-T at 2,000 Meters looks very different.

Now we reached the end of Table VIII Tank Gunnery 1976.   The last engagement was a house—an 8-by-8-foot panel between 1,500 and 2,000 meters from the firing position.  The ammunition is HEP-T—High Explosive Plastic-Tracer, the slowest round that tanks fire.  The actual rounds we fired is not the service ammo pictured above but the powder-blue inert rounds. 

This final engagement was truly different from the preceding three main gun rounds because it was the longest shot with the slowest round.  When we fired APDS “SABOT” rounds at the moving tank target at 1,000 meters distance, the round is traveling just over a mile per second leaving the gun muzzle.  Even allowing for wind resistance, the time to a target roughly 3,300 feet away is less than a second.  The trajectory is essentially flat.  For a tank-sized target, it is point and shoot.

When we fired HEAT at 1,500-meter target, the muzzle-to-target time was more than a second and I could see a ballistic arc, but with a 3,850-foot-per-second speed out of the gun tube, the trajectory was still close to flat.

For the final engagement my gunner was firing at a panel nearly seven thousand feet away.  The HEP-T round has a muzzle velocity of 2,450 feet per second.  So the time to target is nearly 3 seconds (2.7 seconds with wind resistance).  When you fire SABOT at 1,000 meters, it is difficult to see the tracer at all.  Firing HEP-T at this distance, the tracer goes up, up, up in a straight line then drops rapidly at the end of its parabolic trajectory.  

As anyone knows who has watched a 70-yard touchdown pass, the ball appears to go up for 60 yards then drop rapidly in the final ten yards, right into the receiver’s hands.  Actually, the peak of the arc, whether pigskin or HEP-T round is half of the travel time form the gun muzzle to impact. 

So for this final engagement, every skill of tank gunnery was important.  When I issued the fire command, the driver had to stop on what he saw as the most solid, level ground possible.  Any tilt of the tank would send the round off target to the left or right.

For every engagement we had just fifteen seconds from the moment we identify the target until the first round goes down range.  No problem with a flat shot at 1,000 meters. 

On the other engagements, I did not have to be perfect with the range finder.  On this target, I had to have the range right or we would not hit.  While Merc, my gunner, refined his aim, I made sure I had the best possible range, that my head was straight on the head rest and the sight picture was as good as I could get. 

With every other shot, Merc had a round down range fast.  With this one he made sure his sight picture was as perfect before squeezing his electric trigger.

Then he said, “On the Way!” 

I watched the round go down range for what seemed like minutes.  The red tracer went up in a straight line then seemed to drop almost straight down toward the target. 

Before the round hit the target, the loader yelled, “Up!” then clambered up through the hatch.  He wanted to see the round hit. 

Merc had the best view in the gunner’s seat with the sight on the target. 

“Hit!” I yelled on the intercom.  “Damn,” Merc said looking through the sight. 

What I saw through the binoculars and Merc saw through the primary sight was a dust cloud rising around the target, but the most important part of what we saw was that we could see the panel for just a moment after we saw the cloud.  That meant the round strike was behind the panel.  Of course, that could mean we missed by firing over the target, but we were pretty sure the dust pattern said Hit! 

I yelled, “Fire!” 

Merc refined his sight picture then announced “On the Way!”

It looked like another hit. 

I said, “Driver Move Out.” We rolled off the range. 

As soon as the grader left the tank at the ammo point, we started yelling and clapping and congratulating each other.  We unloaded brass and rolled to the rally point.

After night gunnery, which I really don’t remember well, we scored “Distinguished.”

We hit every target during daylight gunnery and range control confirmed we put a hole in the panel on the last engagement. 

Before gunnery that year, I read the entire Dash 10 manual.  I know the TM Number as well as I know my Social Security Number.  9-2350-215-10. 

I am in Army Aviation now and have had some great flights on Blackhawk, Chinook and Lakota helicopters.  But I am not part of the crew.  For the years I was in tanks, I was crew.  It really was the best job I ever had.

Tank Gunnery 1976, Part 6, Moving Truck, Coax Machine Gun

The second to last target on Table VIII is a moving truck panel.  As with the moving tank target, we had practiced tracking moving targets more than anyone else in the battalion.  We were ready to perforate the track mounted panel as soon as we saw it.  But the real preparation for this engagement was done by my loader, Gene Pierce.  The M73 coax machine gun was a reliable weapon in general, but in my experience was finicky about dirt and ammo feed.

The night before Table VIII Pierce cleaned our coax to whatever coax perfection can be.  By the time we reached the moving truck target, we had fired the coax twice in engagements one and four, firing 100 rounds at each firing point.  We had 100 rounds to hit the moving truck, which is plenty, unless the gunner gets interrupted and has to re-acquire his sight picture.

We were tense rolling from the .50 cal. engagement looking for the moving panel.  We also knew pretty much where the panel would be since the moving panels are in roughly the same area of the range.  Pierce was scanning with me, mostly to show the grader we were following procedure, but he was ready to drop down the moment we saw the target and ready to keep the coax firing if anything went wrong.

I saw the target move.  Announced "Gunner! Coax! Moving Truck!"  We stopped smoothly as I swung the turret to the moving panel.  Pierce yelled "Up!"  Merc said "On the way!"  Pierce lightly held the belt of 7.62mm ammo as it fed into the M73 machine gun.  Tracers sailed winked out of sight as the passed through the panel.  Merc knew he was on target and burned the 100 rounds in short bursts.  I announced "Cease fire! Driver move out."

Now we were heading to the last engagement.  The last round on Table VIII is still one of my favorite all-time moments in the Army.

In the meantime, an instructional video on the M73 coax machine gun.

Tanker's Final Exam, Part 5, .50 Cal. Machine Gun, 1200 meters

The commander's cupola with the M85 .50 Caliber Machine Gun is on top of the turret.  

As we rolled away from engagement 6, firing the main gun at a moving tank, next up was firing the .50 caliber machine gun a "truck" target.  Actually a plywood panel.  The target was almost 1,200 meters away.  My loader, Gene Pierce, spotted the target first on a rise to the left of the tank trail.  As we rolled from the last firing point, I made sure the commander's machine gun was in line with the main gun.

When we spotted the target, having the guns lined up meant I could swing the turret with the commander's override and be close to the target.  When the main gun was on target, my .50 cal. machine gun would be close to the target, so I could drop down into the turret and fire as soon as possible.

When I looked through the 1 to 1 sight, I saw the target, so I grabbed the cupola controls and got the gun on target.  I had spent a lot of time zeroing the machine gun on the static range.  And even when I could have shot "cowboy" not using the sights I made myself drop down in the turret and practice with the sights.  A 1,200-meter shot needs the sights.  The other reason I needed the sights was the limited ammo capacity of the cupola.  I had 100 rounds for two engagements.  That's enough if I am on target, but not enough to shoot with my head out.

I squeezed the trigger.  Pierce called hit on the second burst.  I put two more bursts in the panel and said, "Driver move out!"

Tanker's Final Exam, Part 4, Moving Tank

We are now at Part 4 of Table VIII of 1976 tank gunnery at Fort Carson, Colorado.
The previous post described Engagements 3, 4 and 5 which occur at the same firing point. Now I will describe Engagement 6, the moving tank.

We practiced for this shot more than any other.  In fact, I am sure we practiced more than any crew in the battalion.  Several times in the weeks leading up to gunnery, I took my crew out in early evening after everyone else left the motorpool and practiced sighting on moving targets.

Today, I am sure I would be busted to Private for the way we practiced.  We rolled out of the motorpool up on a ridge that looked down on Interstate 25—the North-South highway that passes the east side of Fort Carson. 

From that ridge, the highway was about two miles away, much farther that the distance to the range target.  But since the cars were going 60-70 mph, their speed relative to us was good for practice tracking a moving target. 

To get a good shot at a moving target, my gunner, Merc Morris, had to practice steadily tracking the target.  This took real skill and control.  While my gunner tracked the target, I would look through the range finder.  After a while he could keep the crosshair perfectly steady center of mass on a Chevy Impala or a Ford Pinto. 

Back to Table VIII.  As we moved along the trail on the tank gunnery range, I saw plywood panel target moving right to left.  I called, “Driver Stop!”  Then “Gunner, SABOT, Moving Tank.”  Pierce (Eugene Pierce, my Loader) yelled “Up!” confirming the gun was loaded. He was so fast, I barely finished the Fire Command before he had loaded the main gun.  The range was about 1000 meters so it was point and shoot with the solid-shot SABOT round.  I handed the binoculars to Pierce so he could track the shot from the top of the turret while I watched the round go down range through the range finder.  I was looking for the flash of the tracer disappearing through a hole in the target. 

If I had any doubt Merc would get a first-round hit, I would have been watching through the binoculars from the commander’s hatch, but I knew Merc would get a first-round hit.  When Merc yelled “On the Way” I pushed my helmet against the range finder and opened my eyes as wide as I could.  I didn’t see anything.  Too much dust.  Pierce yelled “Hit!” dropped into the turret, slammed another SABOT round into the breach of the main gun and yelled “Up!”  Merc fired again.  I said, “Driver Move Out” quite sure there were two new holes in the moving-tank target. 

Next engagement was the M85 .50 cal. machine gun at 1200 meters. 

 
This series started with seeing the movie "Fury" and wanting to be back in a tank turret.  Then the first main-gun shot of Table VIII.

Tanker's Final Exam, Part 3, Machine Guns and HE

After the first two engagements, coax machine gun then HEAT at a 1600-meter target, the next two engagements were machine guns against troop targets.

We are supposed to keep moving while firing machine guns.  As we moved away after firing the cannon, I said "Driver Steady" over the headset.  Merc and I had practiced for hours holding our sights steady on an area target while Burhans smoothly steered the tank down the trail.  He held 10 mph while the loader and I scanned the horizon.  The .50 cal. target came  first.  Troop silhouettes off to the left at 1200 meters, almost 3/4ths of a mile.

When Pierce called the target, I swung the turret close to the area, then dropped down to refine the aim through the .50 cal. sight.  Burhans slowed to 5 mph.  I had been cautioned over and over by our platoon sergeant not to "Cowboy" the commander's machine gun.  I only had 50 rounds to bring effective fire on those targets.  That meant the 2nd tracer better be on target, if not the first.  Firing the .50 by eyeball is fun, but not accurate.  I aimed through the site, kept my burst short and put effective fire on the troop targets.

Next were troops at just 500 meters.  As soon as we saw then, Pierce dropped down in the turret in case the coax jammed.  I swung the target in the area and yelled "Gunner, Coax Troops."

Merc took the control and put nearly all of the hundred rounds into those troop panels.  Burhans held us at a steady 5 mph while Merc fired, then eased up to 10 mph again when I called "Cease Fire."

When we rounded the next bend, Merc was ready for the shortest shot, but one that would catch other crews out.  We fired at a panel at 900 meters with High Explosive.  This was the round we fired with the telescope, not the main sight connected to the stereoscopic range finder.

Merc had no problem.  Months of practice and the relatively short firing distance meant he was ready to hit the small panel with the slower high explosive round.  HE has a muzzle velocity of just 2,450 feet per second, less than half the speed of SABOT armor-piercing rounds.  A 900-meter shot with SABOT was point and shoot.  With HE the ballistic path took the round many yards above the target before it dropped through.

When Pierce spotted the target (He was very good at picking out targets.) I swung the turret and yelled, "Gunner HE Anti Tank."

Pierce already had HE loaded and the next round cradled in his arms.

Merc refined his aim.  We waited two extra seconds for this telescope shot but it seemed a lot longer.

"On the Way," Merc yelled and the tank rocked back.  Pierce yelled "Up" announcing the gun was reloaded just a second after the tracer showed that the HE round passed through the panel.  I announced "Hit."  The grader concurred.  Merc yelled "On the Way" and the second round passed through the panel.

I said "Driver Move Out" and tapped Merc on the shoulder with my foot.  Pierce reached over the gun and whacked Merc on the helmet.  We could lose points for unnecessary chatter on the headsets, so Pierce had to jump down and hit Merc on the head, in the most affectionate way.  Pierce was grinning.  He knew we were tearing this range up.  But the next engagement would be tough.  Moving tank.

Tankers Final Exam, Part 2 "Gunner, HEAT, Tank"

After the first engagement, we rolled down the firing lane scanning the trees and dunes ahead on the range at Fort Carson in southern Colorado.  Off to the left just over a mile away, a 6 by 6 wood panel popped and I yelled my favorite fire command into the headset:

Gunner, HEAT, Tank!

At the moment, Burhans brought the tank to a smooth halt.  I traversed the turret left and got the gun on the target.  While the turret traversed Geno loaded a HEAT round into the chamber and yelled "Up" announcing the main gun was loaded and ready to fire. The High Explosive Anti Tank round has a projectile shaped like a whiskey bottle.

The round detonates when the nose of the round touches the target, but the detonation is at the back of the round.  It forms a shaped charged that burns a hole through up to a foot of armor plate.  An explosive shell would not penetrate half that much armor.  The best round for punching through armor plate is the solid-shot SABOT.  We'll get to that later.

With HEAT loaded, Merc moved the sights to center of mass of the panel, shouted "On the way" and fired.  The tank rocked back as the main gun recoiled, splitting the turret in half.  The spent cartridge from HEAT round clattered to the metal floor of the turret.  Geno slammed another HEAT round into the chamber and yelled "Up."  I saw the tracer pass through the panel with my binoculars and announced "Hit."

One of the advantages of HEAT over the more effective SABOT round for the tank commander, is that it is easier to adjust fire.  With a muzzle velocity of 3,850 feet per second, the HEAT round took two seconds to travel from the gun to the target.  The SABOT round covers the same distance in just over a second.  That extra second gives me a better chance of seeing through the huge cloud of smoke and flame coming from the gun muzzle.

Merc refined his aim as he always did, announced "On the way" and fired.  Another round, another hole in the panel.  "Driver, Move Out."

Next, machine guns.

Remembering the Tanker's Final Exam

The Moment After the 105mm Round Goes Downrange

Last post ended when my crew and I lined up for the moving range at my first annual tank gunnery.  It was April 1976.  I had enlisted in the Army the year before after spending 2-1/2 years in the Air Force.  I was a Specialist at enlistment in June of 1975, got promoted to Sergeant in January and was a tank commander.  For the driver, PFC Richard Burhans, and I it was our first gunnery.  For the loader, PFC Gene Pierce, this would be his second annual gunnery.  My loader, SPC "Merc" Morris, had been a loader in the two previous years.  This would be his first time as a gunner.  

And gunner was the position The Lord made him for.

Merc was a rumpled, complaining, lousy soldier in many ways, but was good with numbers and could think quickly and clearly about ranges, ammo and adjusting fire.   

As we rolled onto the range we loaded ammo and waited in springtime sun in Colorado.  Blue sky, little wind, and lots of nerves.  The moving range takes the crew down a lane with nine targets.  Four main gun targets, three coaxial machine gun targets, and two .50 caliber machine gun targets.  The "Coax" machine gun is a 7.62mm, belt-fed weapon mounted parallel or coaxially with the main gun.  The .50-cal is fired by the commander in the cupola on top of the tank.

After the command "Driver, Move Out" we move slowly down the range.  We are all scanning left, right and front for targets.  The first targets pop up to the right: troop targets at 400 meters.

Before I talk about firing, a word about crew commands.  The fire command is primarily for the gunner, but tells the whole crew to do something.  The format is: Alert, Ammo, Target.  So for the first engagement, when I saw the troop targets, I used the commanders override turret control to swing the turret close to the target area.  As I swung the turret, the driver brought the tank to a smooth stop and I said, "Gunner. Coax. Troops."

Merc then brought the sights to the center of the troop concentration and announced "On the way" as he squeezed the trigger.  The loader made sure the ammo belt was feeding smoothly into the coaxial machine gun while the gunner fired.

Before the new tanks with stabilized sights and guns, tanks fired from the halt.  So every time I issued a fire command, the driver's job was to bring the tank smoothly to a halt as level as possible.

Merc put a dozen tracers in the area--a total of 60 rounds.  I called ""Cease Fire!"  And then "Driver, Move Out."

The whole crew scanned for targets.  To the left, a tank-sized panel popped up.  First main gun engagement.

More next post. . .