WesWorld

OTO Melara 120mm Mortar.

Designed as a heavy close-support weapon for both delivery of High Explosive shells and Smoke rounds. Fills a gap in ranged support between the 81mm mortar and the light 75mm field guns (the range is about in-between the 3km of the 81mm mortar and the 9km of the 75's). While there are man-portable carriages, the weapon is intended to be mounted on AFVs. Not related to the smoke grenade launchers on the Princeps and Velites.
Barrel length : 1.9 m
Total weight : 350 Kg
Elevation : +45° to +85°
Traverse : 6°
Muzzle Velocity : 270 m/s
Range : 6,000m

Looks reasonable enough.... in fact, a man portable version would probably be appreciated by the Alpini.

Going back to our conversations about the EP (HEAT) rounds for the 47mm AT gun, I have found a figure for 38mm of penetration @ 30 degrees. The source currently is a forum post and I have contacted the user with a request for where he got the figure. Until I hear back from him or find a source stating otherwise, this is the best information I have to go on with regard to the round's performance. The figure is below the guestiment I made of 45mm, tho that guess was for a zero degree impact. The figures I have on the gun indicate that the historical EP round only exceeded the penetrating performance of the standard AP round at ranges greater the ~500m. Does a figure of 38mm for the baseline EP round sound acceptable? It is also noted by several posts that the EPS rounds mostly differed by better fusing, so the pen would only be marginally improved and still below the standard AP round at closer ranges.

Quoted from "snip"

Going back to our conversations about the EP (HEAT) rounds for the 47mm AT gun, I have found a figure for 38mm of penetration @ 30 degrees. The source currently is a forum post and I have contacted the user with a request for where he got the figure. Until I hear back from him or find a source stating otherwise, this is the best information I have to go on with regard to the round's performance. The figure is below the guestiment I made of 45mm, tho that guess was for a zero degree impact. The figures I have on the gun indicate that the historical EP round only exceeded the penetrating performance of the standard AP round at ranges greater the ~500m. Does a figure of 38mm for the baseline EP round sound acceptable? It is also noted by several posts that the EPS rounds mostly differed by better fusing, so the pen would only be marginally improved and still below the standard AP round at closer ranges.

Going back to my previous position - I would want to see the source for this forum post, as you do as well. If there is objective evidence, I will buy it... but until then, I will withhold judgment.

Given we know the round exists based on US Documentation, good sited documentation here with regards to the nature of the round (specifically post 3), and that the figure sited backs up the repeated claims that the 47mm EP round was worse then the standard AP round at anything close range it seems reasonable to me. After combat experience with the round, some units used the thing as HE apparently.

As an aside, I'm not quite getting the fuss over having something historic around that is known to be way worse then the standard projectile. Its not like Im trying to claim pen close to a 75mm HEAT round.

I don't see it as a fuss so much as a wariness to jump to conclusions, particularly as you're waiting to hear back about an original source. It sounds reasonable, however.

Given the age of the post, Im not sure it will pan out. Which is unfortunate.

While I have not been able to access the source claims for the pen figure given earlier, I have figured out part of why the early EP shells we so crappy and how the EPS shells improved on them. This goes across all the Italian guns, not just the 47mm. The US document on Italian ammo posted earlier supports the claims I have found that most Italian artillery pieces up to 105mm guns were issued EP and EPS rounds. It seems that the EP rounds were originally developed as a way to increase the anti-tank capabilities of the field artillery. To this end, unlike other HEAT rounds they used the same base fuses as found in the HE shells. As one could assume, this arrangement was not conducive to forming a good penetrative jet. This is what lead to the poor pen of the EP rounds. The later EPS rounds adopted a German nose fuse, my guess is something similar to ones found on the Gr 39 HL, that lead to performance improvements. The 100mm EPS shell could supposedly pen the side of an IS-2's turret (90mm @60 degrees), so the later EPS rounds were quite capable. Source. So IMO, there is a clear historical precedent for the development of Italian HEAT shells.

As to how this applies to WW, I proposed the following.
--All guns that received EP rounds as historical get them at the historic time. This places the EP rounds in service in early to mid 1942 on everything below the 105/28 (the 90/53 did not enter service until 1943, so it does not get these shells). I see no reason to stall this development in WW, especially given that the 75/46 AC Mod34 was never employed in its historic Anti-Tank roll. Even tho figures are scarce/nonexistent for these shells, I think it would be a reasonable assumption to make that all of them are strictly worst then the AP rounds for the guns in question aside from at extreme (~1000m) range ,where as we have talked about, hit probability is a greater issue then penetrating power.
--Given that there is no German assistance, the EPS rounds are introduced on a slower timetable, and only for the following guns; 75/18 Mod34/35, 75/32 Mod37, 75/46 AC Mod34, 90/53 Mod43 (ahistoric, but given the noted 100mm EPS shell, I feel it is possible), 105/28 Mod35. Even tho data on the historic shells is lacking, I think there is enough historical data to provide a reasonable figure for the penetration figures for these shells. Given that they would be using home-grown fuses as opposed to German ones, any discrepancies should be explainable by that.

Some initial figures on the proposed WW EPS shells, these in no way relate to figures of the OTL shells. The Wiki artical on HEAT rounds claims that WWII era rounds typically had penetration figures in the 150% to 250% of initial bore diameter. While it is not noted, I assume this is for a perpendicular impact and do not take into account any degradation effects from rifling. Looking at historical data for the German 88mm Gr 39 HL (90mm pen) and British 95 mm Tank Howitzer OQF Mk I HEAT (110mm pen) rounds, the figures quoted are for 30 degree angle. I am also assuming that these figures take into account the effect of rifling, and so form a more accurate baseline then the noted Wiki figures. Running these figures though some math to get LOS thickness gives a 103mm pen for the Gr 39 HL round and 127mm for the British round. For the German gun, this gives a figure of 117% of bore. The British gun has 133%. Based on these numbers, it looks like something in the 125% of bore region is reasonable for the Italian rifled guns. Also, the ratio should be somewhere around 100-115% of bore for a impact at 30 degrees. With that in mind, I propose the following as figures for the WW EPS shells. In parenthesizes, the standard AP round's penetration figures are noted like this (100m/500m/1000m) and all figures are at 30 degrees.

75/18 Mod34/35: What data I have seen tends to peg howitzers as having less capable rounds. For these guns I will use the low 115% figure. 86mm at Perpendicular, which is going to be a very hard shot for a howitzer to make. 74mm @30. (59/48/37)

75/32 Mod37: This will use the same HEAT round as the Mod34/35.

75/46 AC Mod34: Since this gun sees use as the main gun on several tanks (maybe other AFVs in the future as well), it has a more capable round based on 120% of the bore. 90mm at Perpendicular, 77mm @30. (95/75/56)[Note: The AP round figures are tuned down from the German 75 mm KwK 40 L/43 as no figures are available for the historic 75/46]

90/53 Mod43: 125% of bore. 112.5mm at Perpendicular, 97mm @30. (126/109/90) [Note: I have two sources for this gun and have elected to go with the more complete and conservative one]

105/28 Mod35: Because it is a Howizer, 115% of bore is used again. 120.75mm at Perpendicular, 104.57mm @30. (No data) [Note: While 105mm AP rounds did exist at the time, it seems that none were used on the 105/28.]

From these figures the usage of the EPS rounds can be observed. For the Howitzers they are a last-ditch defensive shell; In case of tank load, point, and pray. For the AFV mounted guns, the concept is to engage at longer ranges with the EPS shells until the target reaches about 500m. Then the standard AP shells are to be used. Since hits at range are going to be more difficult for both AP and EPS rounds, it makes more sense to go with the EPS rounds since they are more likely to penetrate outside of 500m. Close-in the standard AP rounds are more effective in both accuracy via muzzle velocity and penetrative power. Anti-Armor ammunition load-outs would likely consist of 65-70% AP rounds and 30-35% EPS rounds. Do these rounds seem reasonable for introduction sometime in the latter half of the 1940's?

No comments?

Quoted from "snip"

No comments?

None other than wondering why the focus on such details?

While others have very complete sets of data to pull from with regards to there guns AT performance, I do not. Therefor, it make sense to me that said performance should be noted and cataloged where the historic data is not available in order to allow a more complete comparison.

Breda Uomo EPS

Improved Man-Portable Anti-Armor weapon introduced in 1948. Larger projectile for improved penetration. The current Breda Uomo EP cannot pen the Triarii or Princeps from the side, so there would be concerns that if possible OPFOR designs were to match the side armor on the Italian tanks that they would be unkillable by the Uomo EP anywhere bu the rear armor. Also, the Uomo EP does not give much margin of error on some current possible OPFOR tanks for anything other then a perpendicular impact. Pen is calculated on 150% of boar diameter, lower then a German weapon being introduced 3 years earlier.

Length: 1450 mm
Caliber: 85 mm
Weight: 6.5 kg Unloaded
Warhead: 4kg fin stabilized. HEAT and HE warheads available.
Range, Maximum: 900m
Range, Effective: 300m (stationary target), 170m (moving target)
Crew: 2, operator and loader, tho can be operated by a single man in emergencies.
Penetration : 127.5mm at 0 degree AoI with 85mm EPS Mod.48 HEAT round.

Who is Italy identifying as their OPFOR?

Yugoslavia is the most likely, but France and Germany cannot be ruled out as there is potential for Yugoslavia to gain support from those nations.

Quoted from "snip"

Breda Uomo EPS

Improved Man-Portable Anti-Armor weapon introduced in 1948. Larger projectile for improved penetration. The current Breda Uomo EP cannot pen the Triarii or Princeps from the side, so there would be concerns that if possible OPFOR designs were to match the side armor on the Italian tanks that they would be unkillable by the Uomo EP anywhere bu the rear armor. Also, the Uomo EP does not give much margin of error on some current possible OPFOR tanks for anything other then a perpendicular impact. Pen is calculated on 150% of boar diameter, lower then a German weapon being introduced 3 years earlier.

Length: 1450 mm
Caliber: 85 mm
Weight: 6.5 kg Unloaded
Warhead: 4kg fin stabilized. HEAT and HE warheads available.
Range, Maximum: 900m
Range, Effective: 300m (stationary target), 170m (moving target)
Crew: 2, operator and loader, tho can be operated by a single man in emergencies.
Penetration : 127.5mm at 0 degree AoI with 85mm EPS Mod.48 HEAT round.

Which German weapon are you referring to? I am somewhat confused.

This.

Broken link!

I'm not entirely sold on the breakthrough doctrine. I could see what you've outlined working well in the deserts of Libya or the EAS, but against well dug in Yugoslav positions in mountainous terrain its going to be harder to aim any kind of breakthrough. Southern Europe is not really suited for tank combat, you need more of an all-arms approach with paras etc. The Germans made great gains in 1941 by surprise and strength and parachutists. It took the Allies a lot of effort to get that territory back with air and material superiority, and In WW most of the area is heavily defended with modern weapons and organised armies. Yugoslav forces wouldn't have to react to an armoured thrust if they can delay an Italian advance and make it costly in losses. I can't really envision an opposite scenario where the Yuogslavs would attack Italy, except perhaps as a spoiling counterattack to threaten your northern cities in that area. I think airpower is the going to be the key here, no matter how many APCs you have operating with tank units.

Should be this...
http://wesworld.jk-clan.de/index.php?page=Thread&threadID=11399
... instead of this...
http://wesworld.jk-clan.de/"http://wesworld.jk-clan.de/index.php?page=Thread&threadID=11399"

Quoted from "Rooijen10"

Should be this...
http://wesworld.jk-clan.de/index.php?pag…&threadID=11399
... instead of this...
http://wesworld.jk-clan.de/"http://wesworld.jk-clan.de/index.php?page=Thread&threadID=11399"

Ah. Thank you Walter.