How accurate are artillery pieces in MOA?
- Thread starter jlbraun
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That's a really good question: I would like to know also.
The only thing I can tell you for sure is that an 88mm gun in the hands of noobs is not that 'accurate.' We fired 76 shells at a double-decker bus a few miles away and only had one partial hit. Of course, that is more a measure of our ineptitude than mechanical tolerances on the gun
But the Iowa: I presume that has very fancy computer-aided stabilization and aiming. I don't know if accuracy is really the right term in the case of the warship because the guns aren't fixed relative to the earth, but maybe we can get some naval gunners in here to set us straight.
The only thing I can tell you for sure is that an 88mm gun in the hands of noobs is not that 'accurate.' We fired 76 shells at a double-decker bus a few miles away and only had one partial hit. Of course, that is more a measure of our ineptitude than mechanical tolerances on the gun
But the Iowa: I presume that has very fancy computer-aided stabilization and aiming. I don't know if accuracy is really the right term in the case of the warship because the guns aren't fixed relative to the earth, but maybe we can get some naval gunners in here to set us straight.
aloharover
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Wonder if MOA in this case is mile of accuracy?
My math may be off but 1moa at 15 miles is 264 inches. So 22 feet. I bet that neither towed arty (105 and 155) is not that accurate.
I also wonder if the exact number, for current systems at least, might not be classified.
My math may be off but 1moa at 15 miles is 264 inches. So 22 feet. I bet that neither towed arty (105 and 155) is not that accurate.
I also wonder if the exact number, for current systems at least, might not be classified.
jwxspoon
Member
Not sure about the exact accuracy in terms of circular probable error although i bet it's pretty low.
My first job in the Army was as a forward observer. We measured everything in mils instead of degrees, 6400 mils to the circle. Pretty accurate.
jw
My first job in the Army was as a forward observer. We measured everything in mils instead of degrees, 6400 mils to the circle. Pretty accurate.
jw
BillinNH
Member
<I remember reading something that the USS Iowa's guns were 1MOA at a distance of 15 miles or something.>
It's been decades since I was a midshipman and studied Naval Science and Gunnery but I recall that the 16" Iowa class guns had a range of 26 miles.
Aiming was thru an electromechanical computer that took into account the range, propellant charge, projectile weight and shape, estimated average wind over the flight path, number of rounds previously fired by that particular gun and the roll rate of the ship and the degrees the target was from from the roll axis of the ship. For a gun that size I believe firing waited until the ship was at the peak (most upright) of its roll. The spotter planes (remember, 26 miles is over the horizon) reported distance and bearing from the splash to the target and the gun crew entered the ACTH (also known as the Jesus Factor) into the calculation for the next round. ACTH actually means Arbitrary Correction To Hit.
So eventually the aiming was spot on after a "sighting in" period.
People with more recent experience please chime in.
Bill
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It's been decades since I was a midshipman and studied Naval Science and Gunnery but I recall that the 16" Iowa class guns had a range of 26 miles.
Aiming was thru an electromechanical computer that took into account the range, propellant charge, projectile weight and shape, estimated average wind over the flight path, number of rounds previously fired by that particular gun and the roll rate of the ship and the degrees the target was from from the roll axis of the ship. For a gun that size I believe firing waited until the ship was at the peak (most upright) of its roll. The spotter planes (remember, 26 miles is over the horizon) reported distance and bearing from the splash to the target and the gun crew entered the ACTH (also known as the Jesus Factor) into the calculation for the next round. ACTH actually means Arbitrary Correction To Hit.
So eventually the aiming was spot on after a "sighting in" period.
People with more recent experience please chime in.
Bill
__________________
Forget WWII or Vietnam accuracies. No modern commander is even trained to consider them.
Direct fire cannon such as from tank cannons use laser or thermal guided optics and are "fire & forget" allowing US & Nato forces to defeat mutliple targets before enemy even realize they've been detected. What you see is where you can hit.
Indirect fire artillery such as the 155mm howitzer is GPS guided to an accuracy of 1mil (3.375 MOA) - this equals a 50-meter box. Modern artillery systems such as the US Paladin use "multiple round-simultaneous impact" (MRSI) capability, which allows one single tube to launch 4 shells at different angles so that they all fall onto a target at exactly the same time. This means that a battery of 6 Paladins can drop 24 155mm shells onto a target at the same time rather than over a period of 2 minutes. To equal that same level of destructive capability, a WWII battery of 8 105mms or 155mm heavies would probably have to expend 200+ shells over a period of several hours.
Direct fire cannon such as from tank cannons use laser or thermal guided optics and are "fire & forget" allowing US & Nato forces to defeat mutliple targets before enemy even realize they've been detected. What you see is where you can hit.
Indirect fire artillery such as the 155mm howitzer is GPS guided to an accuracy of 1mil (3.375 MOA) - this equals a 50-meter box. Modern artillery systems such as the US Paladin use "multiple round-simultaneous impact" (MRSI) capability, which allows one single tube to launch 4 shells at different angles so that they all fall onto a target at exactly the same time. This means that a battery of 6 Paladins can drop 24 155mm shells onto a target at the same time rather than over a period of 2 minutes. To equal that same level of destructive capability, a WWII battery of 8 105mms or 155mm heavies would probably have to expend 200+ shells over a period of several hours.
Dr. Peter Venkman
Member
More accurate than you are trying to hit the inside of the toilet.
I recall reading that the longest actual hit, battleship to battleship, in battle, was 27 miles. From my memory the Italians were using spotting planes to relay the left, right, up and down.
Now someone could figure out, given a 1000 foot ship, and the distance is 27 miles, what sort of MOA does that give?
In so far as shooting against ground targets, you have to factor in the 70 foot divots 16 inch shells leave. I guess a one MOA group could be 140 feet in diameter.
Grunts told me that shells from the New Jersey sounded like freight trains going over head. Rumble, rumble, rumble.
Now someone could figure out, given a 1000 foot ship, and the distance is 27 miles, what sort of MOA does that give?
In so far as shooting against ground targets, you have to factor in the 70 foot divots 16 inch shells leave. I guess a one MOA group could be 140 feet in diameter.
Grunts told me that shells from the New Jersey sounded like freight trains going over head. Rumble, rumble, rumble.
MisterPX
Member
What's 50M at 5 miles convert to?
DevilDog0402
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Don't know but the destructive power of a battery of 155's is SCARY!!
rc109a
Member
I was stationed onboard the USS Wisconsin from 1988-1992. Those guns may have been accurate, but with the fire control system (the system responsible for determining where to shoot) they were not that accurate at all. It did not really have to be all that accurate considering the size of the projectile. Sometimes we hit what we needed to (tanks or other targets) pretty quick, other times we just stopped and let the aircraft take over. They had plans to upgrade the system when we came back, but they alread had plans to decomission the two reamining battleships and the plans were scrapped. I hope that helps...
Zak Smith
Member
Recently got to see a battery of these shoot. The whole operation is complex and impressive. Just like in long-range rifle shooting, it seemed like the accuracy was determined by changes in atmospheric conditions. I think we figured they were hitting "groups" around 1 mil at the distance.
............... Larger version of above photo.
............... Larger version of above photo.
thebaldguy
Member
I've always been told that modern artillery is pretty accurate. The bigger the bore, the greater the accuracy (ie 105MM howitzer is generally less accurate than a 155MM or 8 inch gun) With a good crew and spotter, they can walk in rounds on a target miles away adjusting as they go. I might be off, but I would guesstimate 1-3 moa like a rifle at 100 yds/meters.
rc109a
Member
Field artillery is so much more accurate. The US Army has it down to a science. The US Navy does not practice enough for it to be as accurate. there are just too many variables to be really accurate. I know being on both sides of the firing line...
Finger
Member
If I remember my old NGF, naval guns are more like rifles and shoot more as a direct fire weapon, where arty is more high angle. I rermember the 8" gun SP was a very accurate piece. NGF also kicks ass with it's higher impact velocity.
Sorry for the ramble. The thread jogged my memory. Happens when you get old.
Semper Fi,
Finger
Sorry for the ramble. The thread jogged my memory. Happens when you get old.
Semper Fi,
Finger
Brian Williams
Moderator Emeritus
I have seen a USMC 8 inch gun put 2 non explosive rounds practice in the same hole from far enough away I cold not hear the report of the gun and that hole was within 30 meters of the called in grid coordinates.
Chuck R.
Member
It's been a while since I retired (2005) and a while before that when I was with guns but, given the basic tenants of accurate predicted fire:
Piece location
Target location
Met Data (weather)
Ammo Data (square weight and Muzzle velocity variations, powder temperature etc)
Accurate computations
Then 1st round Fire For Effects (FFE) are doable. When accuracy is really needed IE for a destruction mission on a point target or when doing FPFs (Final Protective Fires) for the grunts, then we’d try to get a registration in. That is shooting a mission by walking the rounds in, then comparing the “did hit” to “should hit” data and applying to corrections to the rest of the firing data. It’s really not down much anymore because with the survey data and lasers it’s usually not needed.
When I was a battery commander many moons ago my old battalion commander would summon all 3 of us firing battery commanders to the “hill” to observe a Battalion “Right by Piece”. It’s when each battery would fire at the same “point” target one gun at a time so the accuracy could be verified/observed. This was for as much bragging rights as to see which gun or guns were out of “sheath” meaning outside what was considered to be normal accuracy. At a couple of the training areas IE NTC 100 meters out of sheath was considered a “firing incident” which required an investigation to find the problem. This was anywhere from 4 to 18 Ks range, further with RAP(rocket assisted projectile) Normal accuracy was considered to be within the effective distance of the burst, so around 50 meters for a 155mm. Normally we shot “circular sheath” and the computer would compute individual aim points per howitzer to maximize the effectiveness of the volley based on ammunition burst radius.
While FA doesn’t measure in measure in MOA, they do have what are called PERs Probable Error Range which calculates the variance by quadrant (elevation or distance) and deflection (Direction) in MILS (about 17.8 MILs to a Degree) and I believe it’s broken down by weapon system and projectile/powder charge, its what used to calculate MSD min safe distance.
The “old” NCOs that I served with often said that the most accurate gun they’d served on was the 175MM which was no longer in the inventory when I came on board. I looked it up in an old TFT (Technical Firing Table) once and the PERs were pretty large, so I don’t know about that. It was more like a naval gun than a howitzer due to it’s higher velocity and lower trajectory.
Keep in mind, I’m a Cold War, Desert Storm era guy and a lot has changed since then.
Chuck
Piece location
Target location
Met Data (weather)
Ammo Data (square weight and Muzzle velocity variations, powder temperature etc)
Accurate computations
Then 1st round Fire For Effects (FFE) are doable. When accuracy is really needed IE for a destruction mission on a point target or when doing FPFs (Final Protective Fires) for the grunts, then we’d try to get a registration in. That is shooting a mission by walking the rounds in, then comparing the “did hit” to “should hit” data and applying to corrections to the rest of the firing data. It’s really not down much anymore because with the survey data and lasers it’s usually not needed.
When I was a battery commander many moons ago my old battalion commander would summon all 3 of us firing battery commanders to the “hill” to observe a Battalion “Right by Piece”. It’s when each battery would fire at the same “point” target one gun at a time so the accuracy could be verified/observed. This was for as much bragging rights as to see which gun or guns were out of “sheath” meaning outside what was considered to be normal accuracy. At a couple of the training areas IE NTC 100 meters out of sheath was considered a “firing incident” which required an investigation to find the problem. This was anywhere from 4 to 18 Ks range, further with RAP(rocket assisted projectile) Normal accuracy was considered to be within the effective distance of the burst, so around 50 meters for a 155mm. Normally we shot “circular sheath” and the computer would compute individual aim points per howitzer to maximize the effectiveness of the volley based on ammunition burst radius.
While FA doesn’t measure in measure in MOA, they do have what are called PERs Probable Error Range which calculates the variance by quadrant (elevation or distance) and deflection (Direction) in MILS (about 17.8 MILs to a Degree) and I believe it’s broken down by weapon system and projectile/powder charge, its what used to calculate MSD min safe distance.
The “old” NCOs that I served with often said that the most accurate gun they’d served on was the 175MM which was no longer in the inventory when I came on board. I looked it up in an old TFT (Technical Firing Table) once and the PERs were pretty large, so I don’t know about that. It was more like a naval gun than a howitzer due to it’s higher velocity and lower trajectory.
Keep in mind, I’m a Cold War, Desert Storm era guy and a lot has changed since then.
Chuck
Dunno if the claims of 1MOA are true or not, but obviously it would be harder for a Naval gun to acheive. Towed or tracked, 105 or 155, artillery ain't fired on the move, let alone with waves.
I've always wondered what the accuracy of that 80cm monster the Germans made was. With a 15 minute "fast" reload time, you'd want it to be something that you'd get your money's worth from. On the other hand, it was a rather LARGE shell.....
I've always wondered what the accuracy of that 80cm monster the Germans made was. With a 15 minute "fast" reload time, you'd want it to be something that you'd get your money's worth from. On the other hand, it was a rather LARGE shell.....
MOA implies that somebody is aiming arty rounds like a rifle. That's not a concept that has any meaning. In Vietnam, when contact was made and a fire mission started, the only for sure thing was that fire was needed and the maybe or maybe not exact location known. FO's , like myself, had a compass and a map and an about knowledge of where we were and where we wanted the fire. We called for base piece first round WP 20 up and watched and listened to flash to bang as an inexact science to see how close it was to where we expected it to be. Then we called for battery fire, ususally half a battery acting as a battery, HE on the deck and then walked it around by direction until we thought we had it in an area that would do some good. And... as was mentioned, the rounds didn't all land in the same spot but within a few meters of each other. This was good.
Range had a lot to do with how accurate arty was too. You didn't want to call in close support from a 105 out at about 8000 meters and beyond on their gun target line unless you had to do so. The rounds got to moving around at a distance on their own and were much less predictable. At max arty range the only way to lesson the chance of killing friendlies, in close support, was to switch to fuse delay for less of a killing radius.
Range had a lot to do with how accurate arty was too. You didn't want to call in close support from a 105 out at about 8000 meters and beyond on their gun target line unless you had to do so. The rounds got to moving around at a distance on their own and were much less predictable. At max arty range the only way to lesson the chance of killing friendlies, in close support, was to switch to fuse delay for less of a killing radius.
Davo
Member
Fascinating posts so far...
trstafford
Member
I also remember reading the article which stated that The Battleships were capable of 1 moa. Keep in mind that when you determine grouping it is not how close you are to a target but to the same point. They fired at a fixed location without adjusting to hit target only to determine the spread on the rounds. I mean who measures there group when shooting at a running deer??
The “old” NCOs that I served with often said that the most accurate gun they’d served on was the 175MM which was no longer in the inventory when I came on board.
You are correct about the 175 being not so accurate. I was in an 8in(M110)/175(M107) unit in Vietnam. The only difference in the hardware was the tube everything else was the same. Keep in mind the 8" is a howitzer and the 175 is a gun (like naval guns). The howitzer shoots in a curved trajectory and is much more accurate than a gun. The 175 was abandoned by the Army after the development of rocket assisted projectiles (RAP) which were artillery rounds with rocket motors in the base. Not as accurate as standard rounds but better than 175s and had the same range, 30 km. The 175 was used a lot for harrassing fire, sensor hits, and other missions that were not danger close (I think 600 meters at the time). Accuracy of the 175 was something like "minute of grid square" we used to say (not really all that bad but The 8 in was kept around because it was the only artillery piece capable of firing a nuclear round and was let go when the cold war was over and the Army got out of the nuclear delivery business in the early 90s and 155s could get the same range with RAP.
I was told an 8 inch was the most accurate artillery piece the Army had at the time. It was supposed to be capable of dropping a round in a barrel at 12miles if everything was correct as Chuck R said. I don't knpw about this but my battery shot missions that were easily within 25-50 meters at that 12 mile range.
Things are different now. FIST (Fire Support Teams) are equipped with laser rangefinders, laser designators, and GPS all of which are a lot more accurate than a compass, map, and eyeball. If the FIST are able to lase a target it will be first round hit on a tank turret at 20+ km. I have seen this happen.
Inaccuracies in artillery were due to human error and the lack of accuracy of the methods used more than the guns.
You are correct about the 175 being not so accurate. I was in an 8in(M110)/175(M107) unit in Vietnam. The only difference in the hardware was the tube everything else was the same. Keep in mind the 8" is a howitzer and the 175 is a gun (like naval guns). The howitzer shoots in a curved trajectory and is much more accurate than a gun. The 175 was abandoned by the Army after the development of rocket assisted projectiles (RAP) which were artillery rounds with rocket motors in the base. Not as accurate as standard rounds but better than 175s and had the same range, 30 km. The 175 was used a lot for harrassing fire, sensor hits, and other missions that were not danger close (I think 600 meters at the time). Accuracy of the 175 was something like "minute of grid square" we used to say (not really all that bad but The 8 in was kept around because it was the only artillery piece capable of firing a nuclear round and was let go when the cold war was over and the Army got out of the nuclear delivery business in the early 90s and 155s could get the same range with RAP.
I was told an 8 inch was the most accurate artillery piece the Army had at the time. It was supposed to be capable of dropping a round in a barrel at 12miles if everything was correct as Chuck R said. I don't knpw about this but my battery shot missions that were easily within 25-50 meters at that 12 mile range.
Things are different now. FIST (Fire Support Teams) are equipped with laser rangefinders, laser designators, and GPS all of which are a lot more accurate than a compass, map, and eyeball. If the FIST are able to lase a target it will be first round hit on a tank turret at 20+ km. I have seen this happen.
Inaccuracies in artillery were due to human error and the lack of accuracy of the methods used more than the guns.
Chuck R.
Member
CRIZZ22,
The 155s were also nuke capable, one of my first "extra" duties was the SWO (Special Weapons Officer) for my HOW Battery that supported 1/11 ACR. I had an assembly team of 4 guys. I hated that job, one of those zero defect areas that only got serious attention when something went wrong. We held a party in either 91 or 92 when the nuke mission went away and we turned our trainer in.
I never served on 8", I did feel sorry for those guys when I'd see them driving around Graf in the winter or covered in dust in the summer. I think it may have left the inventory because the MLRS pretty much took over the long range counterfire mission and the 8" although an awesome platform, was just too slow to fire for DS missions. In 1987 Germany they were all assigned to GS BNs and those were in mixed 8"/MLRS Brigades. My squadron did have an 8" BN as our Reinforcing BN, which was great due to the extended range, but their "Repeats" could be measured with a sundial
I suspected as much about the 175, the tables listed some large PERs for range. I think it's a case of they liked the bigger tube and being on the gun, you never get to see the impact, unless somethings gone seriously wrong.
Sort of the "It looked good when it left here" thing.
Chuck
Chuck R,
You're correct about the 155 being nuclear capable. Forgot what time they did become so. The MLRS appearance on the scene gave mass and range new definitions.
My squadron did have an 8" BN as our Reinforcing BN, which was great due to the extended range, but their "Repeats" could be measured with a sundial
The sustained rate for an 8" is a round every 2 minutes if I remember correctly. Sustained rates of fire (like a lot of other issues) go down the toilet if you need steel on target. There are many Korean War Vets that can testify to that firing Charge 1 or 2, High Angle with a 105 at the Chinese that were only a couple of clicks away (or closer). I experienced this to a much lesser degree in Vietnam. The target was no where near as close. I have seen 3 rounds in a little over 2 minutes with a very good gun crew. Not sustained but 3 quick rounds out. You got a lot more practice in I Corps in Vietnam firing sometimes a couple of hundred rounds a day. Can't remember the exact fiqure but tube life on an 8" was at least a few thousand rounds.
When my battery switched to 175s it was a lot easier. Tube life was 299 Zone 3s (max charge). You rarely shot 175s unless they needed max range so you didn't get that many missions.
Back to the original question. Based on my witnessing the 155 hit the tank turret at 20 km and saying the tank turret is 10 ft it all translates to about 1.8 MOA if my math is correct. That's for it to hit anywhere on the turret. It reality it would be a minute of angle or less. That's using GPS and lasers of course.
You're correct about the 155 being nuclear capable. Forgot what time they did become so. The MLRS appearance on the scene gave mass and range new definitions.
My squadron did have an 8" BN as our Reinforcing BN, which was great due to the extended range, but their "Repeats" could be measured with a sundial
The sustained rate for an 8" is a round every 2 minutes if I remember correctly. Sustained rates of fire (like a lot of other issues) go down the toilet if you need steel on target. There are many Korean War Vets that can testify to that firing Charge 1 or 2, High Angle with a 105 at the Chinese that were only a couple of clicks away (or closer). I experienced this to a much lesser degree in Vietnam. The target was no where near as close. I have seen 3 rounds in a little over 2 minutes with a very good gun crew. Not sustained but 3 quick rounds out. You got a lot more practice in I Corps in Vietnam firing sometimes a couple of hundred rounds a day. Can't remember the exact fiqure but tube life on an 8" was at least a few thousand rounds.
When my battery switched to 175s it was a lot easier. Tube life was 299 Zone 3s (max charge). You rarely shot 175s unless they needed max range so you didn't get that many missions.
Back to the original question. Based on my witnessing the 155 hit the tank turret at 20 km and saying the tank turret is 10 ft it all translates to about 1.8 MOA if my math is correct. That's for it to hit anywhere on the turret. It reality it would be a minute of angle or less. That's using GPS and lasers of course.
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