Artillery Ammunition by lots.

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Delta Tank
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Artillery Ammunition by lots.

#1

Post by Delta Tank » 14 Oct 2014, 14:38

To all,

I have been reading "Logistical Support of the Armies, Vol II" by Ruppenthal and I found this on pages 272 and 273 and thought it was interesting. Having served in the artillery in fire direction I know about ammunition lots and segregation of lots and all that stuff, but I did not know that there was a huge problem with accuracy within lots and between lots. Now, my question is how much difference in meters was there potentially between lots, the book does not state, but it would appear to be large. Carl, any ideas?? Mike
One of the most troublesome problems which plagued ammunition supply through the entire period of operations was the problem of the segregation of ammunition by lot number. Under a system of mass production in many plants there is no guarantee that all ammunition of a single type will have the same ballistic characteristics. Ammunition must therefore be segregated or grouped according to performance characteristics, particularly with regard to range. It is desirable of course, to keep the number of lots delivered to a single battalion as small as possible and, conversely, the number of rounds per lot as large as possible.

Lot segregation was not a new problem,

--273--

and attempts had been made to cope with it before the invasion. Tests carried out in the United Kingdom had shown that variations between lots and even within lots were too great for safety in the close support of infantry, and some nonstandard lots were therefore rejected. Some 800,000 rounds of 105-mm. howitzer ammunition, the type used in greatest quantity for close support, were classified before the invasion. But this quantity was quite inadequate, and units eventually had to be provided classified, unclassified, and even previously rejected ammunition.93 On the Continent the extended discharge over beaches, the continued receipt of many small mixed lots from the United States, the lack of transportation needed for the rehandling of ammunition once it was on the ground, and the October speed-up in unloading, accompanied by the forwarding of ammunition in bulk, all militated against the maintenance of lot integrity.

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bronk7
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Re: Artillery Ammunition by lots.

#2

Post by bronk7 » 11 Nov 2014, 20:28

add weather/climate/age of weapon/ and you would think it would greatly affect targeting .....but isn't that what the FOs were for?..the greater the distance, of course, would have a greater error?....I would think the lot variation couldn't have been too great, or wouldn't you have many more friendly fire casualties? what does it mean by ''Ammunition must therefore be segregated or grouped according to performance characteristics''<>per lot?? interesting post, ty--I enjoy these ''small details'' of the war posts


Delta Tank
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Re: Artillery Ammunition by lots.

#3

Post by Delta Tank » 11 Nov 2014, 21:32

Bronk7,

I was kinda of hoping that Carl would jump on this post and explain it, I was an enlisted FDC guy in Arty and 4.2 inch mortars and I understand that lots could have different firing characteristics, but I never thought it would be so great that a call for fire could endanger the troops requesting the fire. I found this passage both interesting and frightening!

Mike

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bronk7
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Re: Artillery Ammunition by lots.

#4

Post by bronk7 » 12 Nov 2014, 01:10

yes, that's what I was thinking....I was 81 mortars.....I have a nice WW2 collection from my uncle, and I remember he said the Germans were good with their mortars, one of the few things I ever heard him say of the war...yes, as I said, very interesting

Carl Schwamberger
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Re: Artillery Ammunition by lots.

#5

Post by Carl Schwamberger » 13 Nov 2014, 07:32

Delta Tank wrote:Bronk7,

I was kinda of hoping that Carl would jump on this post and explain it,...
Had no idea was wanted here.

If there is a 1% difference in range performance between two propellant lots then at 5000 meters range that would translate into a average of 50 meters difference in mean point of impact. Not very significant if you are just trying to suppress or keep their heads down. If you are really trying to kill people or destroy things then 50 meters is more important. Plus if you are trying to make up the difference with adjustments from the observer then there is more warning & more time to take cover or move from the target area.

In training it was hard to see the differences between lots. We seldom had two different lots on hand, & so little ammo was fired each day the differences did not show clearly.

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bronk7
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Re: Artillery Ammunition by lots.

#6

Post by bronk7 » 13 Nov 2014, 14:44

Carl Schwamberger wrote:
Delta Tank wrote:Bronk7,

I was kinda of hoping that Carl would jump on this post and explain it,...
Had no idea was wanted here.

If there is a 1% difference in range performance between two propellant lots then at 5000 meters range that would translate into a average of 50 meters difference in mean point of impact. Not very significant if you are just trying to suppress or keep their heads down. If you are really trying to kill people or destroy things then 50 meters is more important. Plus if you are trying to make up the difference with adjustments from the observer then there is more warning & more time to take cover or move from the target area.

In training it was hard to see the differences between lots. We seldom had two different lots on hand, & so little ammo was fired each day the differences did not show clearly.
I was going to mention 50 meters as a starting point [ if you can believe me ] but, for big guns, 50 meters doesn't seem like much...my question is, with an average gun team, say for 105mm gun, how close to the target would the first round hit..is that even possible to research? even with line of sight targets, I never saw a ''super'' close first round hit when I was in mortars...and with FOs,/etc, I would think there would be a lot of adjustments from the FOs, so, even 100 meters sounds like a good first shot..ty all replies

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Re: Artillery Ammunition by lots.

#7

Post by Sarek » 22 Nov 2014, 01:30

Dear Bronk7,

I was a FO in the Swedish army and directed 120mm mortars (6000m range) and also both different sorts 105 mm (20000m range) and 155 mm gun (300000m range) batteries.
I would guess I have seen some 50 separate fire for effects during my training.

I only saw one (1) hit spot on target with the first salvo or directing shot.

As a forward observer I knew that the map (1:50 000) are at the least 50m wrong in accuracy. That is for both me and the firing battery. That gives 100m fault from the start. And the weather and wind up in the sky etc.
The lots of the propellants must be seen seperatly as they are fired.

But we emphasised shooting on half ranges to minimize the effects of the spread.

Yours truly,
Sarek

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bronk7
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Re: Artillery Ammunition by lots.

#8

Post by bronk7 » 29 Nov 2014, 17:11

Sarek wrote:Dear Bronk7,

I was a FO in the Swedish army and directed 120mm mortars (6000m range) and also both different sorts 105 mm (20000m range) and 155 mm gun (300000m range) batteries.
I would guess I have seen some 50 separate fire for effects during my training.

I only saw one (1) hit spot on target with the first salvo or directing shot.

As a forward observer I knew that the map (1:50 000) are at the least 50m wrong in accuracy. That is for both me and the firing battery. That gives 100m fault from the start. And the weather and wind up in the sky etc.
The lots of the propellants must be seen seperatly as they are fired.

But we emphasised shooting on half ranges to minimize the effects of the spread.

Yours truly,
Sarek
I never thought of map discrepancies...good point...what do you mean propellants seen separately?? once again, thanks to all...these posts are very interesting and informing to me...Swedish army <>very interesting....120mm was only 6000m?? how heavy was the round??

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Re: Artillery Ammunition by lots.

#9

Post by JonS » 30 Nov 2014, 04:20

The problem with mixed lots and batches is not so much in the adjusting - given enough time and rounds any muppet can eventually get rounds onto the target. The problem is to do with consistency. The point of the adjustment procedure is to account for all the corrections-of-the-moment - stuff like air temp, charge temp, winds, specific barrel wear, etc - so that at the end of the adjustment process you know that lands will land on and around the target. But if you have mixed lots and batches, you are introducing a factor that adjusting can't take account of - some rounds will land on, and others will land long or short of the target, depending which lot/batch they're from and which lot/batch was used in adjustment. That's a waste of rounds, and potentially highly dangerous for any supported infantry (both in terms of short rounds landing in their midst, and long rounds failing to suppress the target)

By separating the rounds by lot/batch, the observer (and the CP) and be sure that the next round will behave the same as the last round, rather than wondering whether that 50m error was due to the rounds being slightly different weights and shapes, or some other factor they can control for.

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bronk7
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Re: Artillery Ammunition by lots.

#10

Post by bronk7 » 30 Nov 2014, 15:55

good point JonS.....if 1 is long by 50, correction to drop 50, lot is bad by 50, that's a 100 meter drop because of lots....possible danger close to friendlies...

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Re: Artillery Ammunition by lots.

#11

Post by ChristopherPerrien » 30 Nov 2014, 16:59

On tanks, we had ballistic computer adjustments for LOT round adjustments.I only recall once having to imput them "before zeroing", for one specific LOT of Ammo, they sent down some "pre-sets". This may have occurred other times and I simply don't remember any other "pre-sets" I guess most of our tank ammo was all perfect "spec" as manufactured and passed through quality control as identical from LOT to LOT with only minor adjustments from tank to tank. I do recall , Master -gunners /TC's /some gunners getting really picky over being sure one tank only had one LOT number of ammo, during a "shoot", and trying to make homogenous LOT load-outs out of several LOTS. If your tank gunnery "shoot" hit near the end of a training cycle, you could get a batch of ammo composed of all the unfired rounds from many other unit "shoots", A LOT nightmare (3-5 LOTs mixed), this rarely happened.

Wish I could remember the pre-sets for that one odd-ball LOT, as one click supposively moved the round hit 3 inches at a bore-sight/zeroing range of 1200m.

All this ammo was "training" ammo, I do not know if any of our actual "black" ammo had pre-sets, we never went so far in an ALERT to zero guns with the 'black" stuff.i.e.- WWIII

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Re: Artillery Ammunition by lots.

#12

Post by Delta Tank » 09 Dec 2014, 18:29

To all,

I left active duty Field Artillery in 1978, back then "Danger Close" was fire within 600 meters of friendly troops. From what I got from the passage in the book quoted above was some of these lots were so bad that if you registered with one lot (should be largest lot on hand) and did an adjust fire mission with a smaller lot, that the initial round would be so inaccurate that it could in fact endanger friendly troops. So, with that thought in mind, I was thinking that maybe the initial adjusting round may land 100's of meters from the target. Even between lots the difference should not be that great. It has been a long time, and the FDO would make the decision on which lot we would use if we had more than one, but I don't recall the ammunition being that bad between lots. A lot of the ammo we fired in the 70's had been manufactured during the Korean War, some from the WWII era.

Mike

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Re: Artillery Ammunition by lots.

#13

Post by Yoozername » 27 Jul 2016, 21:12

Interesting discussion. As a cartographer in the military, I can assure you that map error of 50 meters is not even remotely possible even for WWII (US Army) maps. Basically, I made maps with the same general technology that was used in WWII.

The corners of a map are extremely accurate from a precision standpoint. These are surveyed in, of course, and the corresponding divisions are based off them. If there is a common error in maps, it is the elevation lines which are produced using stereoscopic glasses and overlapping photos. The points on the elevation that are marked with a triangle (i.e. "Hill 219), is an accurate surveyed landmark. If anything, end-user errors...people that can't read maps or know where they are, is the major error.

I think people are mixing some statistical jargon here. The greatest error in indirect fire comes from velocity variations. We are talking precision needed way below 1%. If you were firing at 500 M/s, and had shells actually leaving at 495-505 M/s, this error would be the main cause of the inaccuracy (aka Dispersion). The greater the range, the greater this is compounded. Other elements like weather, etc. combine to make your precision fire like a Katyusha bombardment.

Artillery forward observer corrections are probably one of those Hollywood deals that even artillery men (Ok, let's even say JonS), might not fully grasp. That is, there are two components to the innaccuracy, one is range and the other deflection. Any FO worth his salt knows that deflection (left and right from line of fire), needs to be 'nulled-out' first. This is because, even at great ranges, this element of the innaccuracy is actually smaller and more predictable and correctable. Once the deflection is 'online', the artillery fire is at the hands of the Gods of Statistics. This is because of the much greater dispersion in range that makes the FO's corrections a case of someone chasing its tail. As an example, a FO could get the deflection inline for the deflection, see where the last shell landed (50 meters long), call in a range correction (back 50 meters!), and the next shell lands in the same exact spot. How is this possible? The answer is that the BEST case dispersion along range might be 100 meters +/- the actual target! Anyone that screams into the radio "UP 50, OVER 100" has made Danger-Close, well, closer.

What the FO might have done was observe where every one of the deflection corrected shells landed since they were all basically being fired at the same range. This characteristic, that is where they all about landed, might clue him (or her...or JonS) in as to the actual mean value that the beaten area will be. Not that easy under combat conditions if other things are going on, of course.

So, even with 'matched' projectiles, and powder-weights with consistent mixes and moisture etc., you are only going to get so good. And, unfortunately, that spread is towards your position. Since the enemy trench is at a 90 degree angle to this dispersion, you get the picture.

People seem amazed that mortars can be accurate. The trick is to use them at short range as a form of assault weapon. At longer ranges, both the deflection and range errors go way up. In fact, instead of an oval shape, it is more circular.

Normandy was a cluster in many ways. The unloading and planned stacking of ammunition became a debacle as the hedgerows became dumping grounds. Some shortages, like mortar ammunition were in fact, just not knowing where everything was. The use of artillery was very tricky in the bocage and mortars, and white phosphorous, became critical. Given the shooting spree that followed, I bet all lots were mixed up and the Germans 'hugged' the front line and like the VC in Vietnam, felt a little safer holding onto the enemies belt buckle.

An interesting story is that US 155mm howitzer crews felt they were much more accurate than the 105mm guys. They even requested giving tactical fires to the infantry in Normandy but it was felt that was too dangerous.

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Re: Artillery Ammunition by lots.

#14

Post by Carl Schwamberger » 31 Aug 2016, 02:21

Looks like this thread is necroed.

Yoozername wrote:...

Artillery forward observer corrections are probably one of those Hollywood deals that even artillery men ....

What the FO might have done was observe where every one of the deflection corrected shells landed since they were all basically being fired at the same range. This characteristic, that is where they all about landed, might clue him (or her...or JonS) in as to the actual mean value that the beaten area will be. Not that easy under combat conditions if other things are going on, of course.

...
This point illustrates the difference between a well trained FO and a average. Running through the task by the numbers is ok for learning it, but there is a lot of skill that was not taught in the accumulated eight or nine day of observation training of the 2d Lt. I was fortunate to have had some useful follow on instruction from a better than average battery commander. Thank you Bill Smith. Its unfortunate that my peers often refered to observation or gunnery skills outside of and above the basics as "Black magic" or 'winging it'. The reality was these artillery leaders, officers & NCOs simply had a broader & deeper understanding of cannon gunnery. Well, most of the time. Sometimes we did make a unscientific guess in the heat of the moment.

Getting back to the propellant Lot question. I suspect the reality was the 'short rounds' endangering friendly infantry were more often the result of errors by cannon crew. From multiple sources, including my own observation accumulated over ten years in artillery training is a charge error out numbered all other errors together. There are many ways this could happen, but I suspect propellant Lot difference were much less important than a error in charges loaded. Another and uglier condition is bad propellant. I recall one unfortunate moment when I discovered the crews had been load propellant with disintigrating fabric bags. They had to handle the bags with extreme care, and its was clear many had broken open. When I checked the records of fire with the FDO its was clear the accuracy was affected in a major way. Given the haste and scale of ammunition storage in transit & in the UK or the Normandy dumps I strongly suspect damaged or wet propellant was a problem, perhaps or perhaps not recognized then, but certainly lost to sight since.

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Re: Artillery Ammunition by lots.

#15

Post by Sheldrake » 31 Aug 2016, 12:14

Different ammunition lots may vary in projectile weight and shape and propellant characteristics and filling. Different manufacturers might use slightly different manufacturing techniques and materials. WW2 was fought in the era before "total quality management" or Baldridge. In the 1940s it was commonly believed that there was a trade off between quality and cost and the optimum was at the bottom of a "U" curve - and military contracts were usually awarded to the lowest bidder....

I don't know how widely ammunition varied in WW2 but as an extreme some WW1 6" howitzer ammunition varied in projectile LENGTH by four inches.

You don't want to adjust fire with ammunition with one characteristic and go to effect with ammunition with a different trajectory. At fire for effect, particularly form several batteries,

The command post should order the ammunition to be fired and the gun line section commanders should ensure that ammunition used on a particular mission conforms. IIRC the two missions which should be fired using ammunition from the same lot were #1 Destruction and #2 Danger Close

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