105mm guns being replaced by 155mm ...?

[bojan]

19 minutes ago, Rick said:

Is 105mm the largest artillery that horse teams routinely pulled?

Older Soviet 122mm (moderznized 122mm model 1909/37 and 1910/30) were also horse pulled.

[Junior FO]

Some general thoughts on the interrelation of calibre, energy, weight and effect. Only in German unfortunately. From 1965 so the ammunition weights are for old charge+cartridge system. He assumes max range is twice a given calibre.

 

Even if you can't read the text the graphs are interesting:

Bild1: Relative necessary number of shots as a function of calibre to achieve a given effect

Bild2: Necessary muzzle energy as a function of calibre to achieve a range in Km of twice the calibre

Bild3: necessary muzzle energy over the maximal range of a calibre

Bild4: Munitionsweight, 1:Densityindex of shell, 2: 1: relative to weight of shell, 3: relative weight of resupply

Bild5: Resupply weight as a function of range of shot

Bild6: Relative average rate of fire as functon of calibre

Bild7: Barrelerosion, reduction of barrel life with increase of muzzle energy

Bild8: Relative average muntionallocation as a function of calibre

 

https://www.e-periodica.ch/digbib/view?pid=asm-004:1965:131::900#192

Edited May 9, 2022 by Junior FO

[rmgill]

Is this a 15cm piece? 

[Markus Becker]

On 5/8/2022 at 12:54 PM, bojan said:

Older Soviet 122mm (moderznized 122mm model 1909/37 and 1910/30) were also horse pulled.

By the looks of the wheels so were older German 15cm pieces. In WW2, in the not so great war they were probably all horse drawn. 

[CaptLuke]

12 hours ago, rmgill said:

Is this a 15cm piece? 

I'm thinking this is a  German 150 mm s.F.H. 18 being towed in two loads.  This is just the barrel; the carriage would be towed separately by another team of horses.  When towed by a semitrack, it was towed in one load.

From Tank Archives:

Quote

 

The gun was disassembled for transport by horse, the weight of each carriage totalling up to 4 tons. The top speed when towed in this form was 8 kph. The s.F.H. 18 could also be towed by tractors at a top speed of up to 60 kph on a paved highway.

With the appearance of the Sd.Kfz. 7 halftrack in 1938, the gun could be towed without disassembly. The barrel was pulled back to travel position. The top towing speed was 40 kph. If the gun was transported separately, it took 5-7 minutes to bring it back to combat position, a complex process that required eight men. When transported in one piece, it only took 3-4 minutes.

1300 mm fully metallic wheels were used when the gun was towed by horse. When it was towed with a tractor, 1230 mm wheels with solid rubber rims were used.

 

 

Edited May 10, 2022 by CaptLuke

[bojan]

On 5/8/2022 at 2:22 AM, 17thfabn said:

...

For the USSR dealing with the road conditions they faced and the vehicle they had the D-1 was better for THEIR situation.

The M-1 155 mm was better for the U.S. 

There were complains from US artillerymen during WW22 that 155mm M1 howitzer was a bit too heavy for a role, and it bogged too easily on the bad roads, despite having excellent prime mover. That echoes local experience, that 155mm M1 howitzer is just a bit too heavy (and also clearance was relatively low which compounded problems with soft soils). Estimate was that such howitzer should be about  5000kg. Basically, what army wanted was pre-WW2 Skoda K-series, which had ~5t weight and  fired 42kg shell to the 15km range. Which was a pretty damn good for early 1930s weapon...

 

Edited May 10, 2022 by bojan

[CaptLuke]

Long, but well thought through, article on the UK's options for replacing the L118 from Think Defense here.

Turns out Turkey has just put an L118 equivalent into production, the BORAN 105mm Towed Howitzer.

[EchoFiveMike]

Seems a 127mm tube circa L35-40 using 155mm modular charges would be the best option.  Heavier throw weight, commonality with existing shells, to include ER and guided types. 

There was the V2C2 105mm project, seemed to have a lot of potential but never fielded anything, as per typical US projects.  Maybe not enough politicians got greased, or it offered too much utility to actual Americans.  S/F...Ken M  

[bojan]

You have described a western version of 130mm M-46. It used ~same charge weight as little known 152mm M-47 gun and improved range from 20.5 to 27.5km. So 34% increase in range for basic shell, not bad at all.

[EchoFiveMike]

I'm not certain it would be worth the full charge, like the USN L54/62, but using the 155mm MACS, as they did with the LEO-105mm would standardize on propellants, maybe chamber volume to throw the 70lb 127mm HE shell at 2500fps or so, for circa 20-22km range.  You could use Volcano or similar for extended range, which is a low % employment anyways.  S/F....Ken M

[KV7]

As above I think medium pressure and very lightweight 155mm better fills a niche than high pressure ~ 127 mm. Hitting stuff 20 km away really should be covered by existing and prospective long range systems. If it can be limbered to a light truck then you can assign it to lower organisational levels.

[17thfabn]

22 hours ago, EchoFiveMike said:

Seems a 127mm tube circa L35-40 using 155mm modular charges would be the best option.  Heavier throw weight, commonality with existing shells, to include ER and guided types. 

I think there is ZERO % chance of any new calibers of tube artillery being adopted by Western Armies. 

Anything that can't be done by the 105 mm or 155 mm will be done by rocket's or missiles. 

[lucklucky]

https://www.thinkdefence.co.uk/2022/02/the-l118-105mm-light-gun-replacement/

[CaptLuke]

On 5/13/2022 at 6:51 PM, EchoFiveMike said:

Seems a 127mm tube circa L35-40 using 155mm modular charges would be the best option.  Heavier throw weight, commonality with existing shells, to include ER and guided types. 

There was the V2C2 105mm project, seemed to have a lot of potential but never fielded anything, as per typical US projects.  Maybe not enough politicians got greased, or it offered too much utility to actual Americans.  S/F...Ken M  

That's not too different from the 120mm KARIN, a 120mm coastal artillery gun on an FH77B mount, though I agree 127mm would make more sense given the commonality with naval use, both for dumb rounds and for smart rounds (e.g., Vulcano). 

There's also the advantage that a saboted version of 127mm smart rounds can be fired from 155mm pieces, an opportunity the USN and US Army have long seemed blind to.

Edited May 16, 2022 by CaptLuke

[bojan]

IIRC Israelis had whole series of saboted artillery rounds, as there was sort of range duel going with Syria. 155, 175 and 203mm versions were produced, but I have no idea how much of each was used, except that but 175 and 203mm versions did see some service in 1982.

[bd1]

is the Mandus Hawkeye 105 dead?

[KV7]

Sabot rounds are good, but to get the full benefit of them the velocity needs to go really high. Unless this is achieved equivalent range can be obtained from a full bore round with ramjet assist, though even here the rounds will be much cheaper, though perhaps also incurring more barrel wear.

[bojan]

 Ramjet w/o guidance is... not optimal, as dispersion will be additionally increased.

[maxwellbest]

Rumint suggests 105 light guns may supplied to Ukraine by UK with training on them to be undertaken by UK/NZ...guess not much use in the attritional battle under way in the Donbass..but easily deployable with no shortage of ammo globally...source is yt so we will see...

[KV7]

On 5/17/2022 at 10:06 PM, bojan said:

 Ramjet w/o guidance is... not optimal, as dispersion will be additionally increased.

Some guidance is IMO required for ramjet assisted munitions, hence the 'though even here the rounds will be much cheaper'.

In general though as GPS guidance gets cheaper and as ranges increase, the case for GPS guidance increases. Very long range unguided fires using sabot ammunition is going to be of low intensity of effect, especially compared to MLRS.

As above if there is a place for sabot rounds today I think it is using very high velocity and guidance, to fill some sort of  'long rang sustained precision fires'  role. The advantage over MLRS is that the ammunition can be much more compact and easy to (re)load, and the advantage over ramjet assist is that at very high velocity the range attainable is even higher. But to get that very high velocity you need a specialised gun and at some point you need to go to a smoothbore. 

Edited May 26, 2022 by KV7

[maxwellbest]

Pardon my ignorance, but isnt GPS jammable?  Thus rendering GPS munitions suspect?  I can recall watching a film on the effects of artillery during  my service days,  VT fuses...they could be spoofed, correct me if I am wrong. 

[KV7]

5 hours ago, maxwellbest said:

Pardon my ignorance, but isnt GPS jammable?  Thus rendering GPS munitions suspect?  I can recall watching a film on the effects of artillery during  my service days,  VT fuses...they could be spoofed, correct me if I am wrong. 

It is a potential issue, and creates a case for some form of INS. But here costs start to rise somewhat again.

[rmgill]

13 hours ago, maxwellbest said:

Pardon my ignorance, but isnt GPS jammable?  Thus rendering GPS munitions suspect?  I can recall watching a film on the effects of artillery during  my service days,  VT fuses...they could be spoofed, correct me if I am wrong. 

It does provide another emitter source. GPS is jammable locally I think, harder as the signals are coming from the sky. Unless you're trundling around with GPS jammers all the time, there's some level of delay between when you turn them on and when you turn them off. 

[shep854]

Speaking of GPS shells…

 

[Junior FO]

On 5/5/2022 at 8:39 PM, rohala said:

how does the accuracy of a 105mm gun and a 120mm mortar compare?

Got to where my old manuals are and had a look. Since our 105's were on the way out when I received them, they don't have the 105 data, but the manaul on the theoretical foundations of artillery firing uses our 105 howitzer in some of it's examples.

In short my previous assumption that the accuracy isn't too much different is wrong. Coloured by my shooting with them, but of course the ranges were 5-7km instead of 15+ that would apply to the 105.

 

General information on artillery spreads:

Dispersion follows a Gaussian curve with one 50% longitudal spread (S50L) having 50% of hits, 2xS50L having 82%, and 4xS50L having 99%.

Groupings of low round count fires can show 0.5-2 x the S50L.

Battery S50L will be approx 1.5x of a single guns,

Battalion S50L will be approx 2x of a single guns)

 

Rules of thumb for Battery S50L in meters

155mm L39 M109 (max22km) = 0.5% of DtopKm (topographical distance in Km) (example 0.005x18000=90)

155mm L47 M109 (max30km) = 0.7% of DtopKm out to 15km, 1% to 21km, 1.4% at 30km

105mm Howitzer = 0.7% of DtopKm

105mm Hvy Cannon= 0.7%/0.8% of DtopKm depending on ammo

 

To note, our 105mm are all WWII vintage.

 

The slope of the receiving ground will modify the above.

 

120mm M113 Mortar= 1.3% of DtopKm (this is more a CEP due to mortars having a different dispersion pattern)

 

 

 

Breadth spread (S50B) in meters is 1xDtopKm

A Battery shooting at a single point can expect to have a breadth of 50m.

A Battalion shooting at a single point can expect to have a breadth of 70-100m

 

Height spread is S50L x tan (impact angel measured from the ground)

 

 

 

 

 

Edited June 11, 2022 by Junior FO