Germany’s New Light Howitzer: the 7.5cm le.IG 18

RIA’s catalog page on this gun

In the aftermath of World War One, every military force immediately began to assess what they thought was most important to improve in their arsenals for the next war. For Germany, one thing they felt lacking was a light howitzer that could be organic to infantry units, mobile enough to remain with the front lines in an advance to provide easy and immediate supporting fire. The Rheinmetall company would develop just such a gun and the German military adopted it in 1932 under the designation 7.5cm leichtes Infanteriegeschutz 18.

The 7.5cm le.IG 18 fired a roughly 12 pound (5.5-6 kg) 75mm high explosive shell out to 4,000 meters, and was capable of both direct and indirect fire (elevation maxed out at 90 degrees). These guns would see service on all fronts with the German military in World War Two, remaining inservice throughout the entire war.

The mechanical operation of the gun is rather unusual for an artillery piece, with a fixed breech and a barrel which tips up from the muzzle for loading and ejection. This did not really convey any particular advantage, but it also did not have any particular weakness and was quite satisfactory in action.

42 Comments

  1. The gun is very similar in concept to the Japanese 70mm type 92 (1932) battalion support gun, which was also used throughout WW2;

    https://en.wikipedia.org/wiki/Type_92_battalion_gun

    The gun’s wheel suspension is interesting in that it seems to be a scaled-down rendition of the torsion bar suspension of the PzKw III and IV tanks.

    Incidentally, the two tanks behind Ian in the opener were an M5 Stuart in the foreground and an M41 Walker Bulldog behind it.

    cheers

    eon

    • ~75 mm infantry gun was popular solution in inter-war period.
      Closest Soviet equivalent of 7,5 cm le.IG 18: 76 mm regimental gun M1927
      https://en.wikipedia.org/wiki/76_mm_regimental_gun_M1927
      Shell mass dependent from particular type, but most types: 6…6,5 kg, range up to 8550 m.
      Although heavier than German counterpart (740…780 kg /with wooden wheels/, 903-920 kg /with metal wheels/ vs 400 kg of German one) it also could be quite easily moved around by muscles of its crew.
      Rough U.S. equivalent: 75 mm Pack Howitzer M1
      Rough Italian equivalent: Obice da 75/18 modello 35

    • What was unique for WWII Wehrmacht was 15 cm sIG 33 which stands for schweres Infanterie Geschütz. Notice that 150 mm infantry gun. It was light for its caliber (around 1800 kg) and widely used by Germans (around 4600 examples made), yet so far I know there was not equivalent in Allied arsenal of this gun.

    • “(…)torsion bar suspension of the PzKw III(…)”
      I presume under “PzKw III” I should understand Panzerkampfwagen III Ausführung G.
      Notice not all version have torsion bar suspension, see: https://de.wikipedia.org/wiki/Datei:Panzer_III_LW.svg
      Also, first production tank with torsion suspension was if I am not mistaken Landsverk L-60, which was offered for export, but I do not know if Japanese were interested in this design, anyway so far I know Japanese tanks of WWII do not use torsion bar suspension.

      • Correct. Japanese tanks between the wars and up to 1945 were based largely on Vickers practice, and most used the various forms of Vickers suspensions, first the unit-sprung type of the Vickers medium of 1922, then the crank-sprung “paired” double bogie type of Medium C from 1929, and finally the leaf-sprung “over and under” setup of the Vickers 6-ton of 1934.

        There was also the horizontal-coil spring setup used on the Type 97, which seems to have been an independent development.

        cheers

        eon

  2. Germany tried to”hide” a lot of artillery with an -18 designation.
    – Flak 18 20 mm
    – FK 18 75 mm
    – Flak 18 88 mm
    – Le FH 18 105 mm

    and others.

    • “Flak 18 20 mm”
      Could you write more about that? I know about 3,7 cm FlaK 18.
      Anyway, in effect of disarmament after 1918, Germany was forced to develop new artillery systems, unlike others states which might maintain older patterns in service and often they did it, as it was cheaper and does not present risk of failed development.

    • Quite likely the Austrian piece was the inspiration. In general the lIG 18 was pretty direct continuation of the light WW1 7.58 cm “Mine Throwers” (Minenwerfer in German), which were used successfully in support of the “Stormtrooper” tactics for reducing enemy strongpoints¹. The “Leichter Minenwerfer 7.58 cm n. A.” (new type) could even be used in direct fire mode. The obvious problem for direct fire was the muzzle loading of the WW1 Mine Throwers, which the lIG 18 fixed.

      Eventually this type of infantry gun lost to the Stokes-Brandt type smoothbore mortar, but that wasn’t obvious after WW1. The smoothbore mortars were not capable of direct fire, which some may have consided a significant shortcoming. The Germans did have 81mm mortars, so they obviously did not consider them a replacent for the infantry gun. Some would argue that a direct fire support weapon is still needed, which explains the continued popularity of such weapons as the 84mm Carl Gustav recoilless rifle in support role rather than as an anti-tank weapon. The Russians have also developed a HE-frag warhead for the RPG-7 and the RPO series of disposable thermobaric (or incendiary) rocket launchers.

      ¹ The original designation of the lIG 18 was in fact “Leichter Minenwerfer 18 (l.M.W. 18)”, pleas see my other post for source.

      • “Russians have also developed a HE-frag warhead for the RPG-7 and the RPO series of disposable thermobaric (or incendiary) rocket launchers.”
        IIRC there were cases, when U.S. forces used Bazooka launchers against pillboxes in PTO.
        Late in war British developed Ordnance, RCL, 3.45 in weapon which was recoilless rifle firing HESH round, which would make it well-suited for wallbuster role, but it was never used in combat as war ended before they could make satisfactory weapon.
        Soviet Union developed thermobaric warheads for reusable grenade launcher, as well thermobaric version of disposable grenade launcher. Examples: RShG-2 (derived from RPG-26 disposable), TBG-29V (thermobaric ammunition for RPG-29 “Vampir” reusable), other nations also developed warheads for theirs grenade launcher for usage against other (non-tank) targets, example is German Bunkerfaust.

  3. The description text says the gun could be elevated to 90 degrees – if true that seems um, inadvisable. In the video it looks like maybe 45 or 50 degrees was the limit. Sad that the action is welded shut. More please.

    • Welding the breech shut is probably to prevent “oops I blew up Mr Wilson’s car/house/lawnmower” incidents. People who cannot be trusted to point guns away from their friends are usually less trustworthy with artillery. And why point the barrel into the sky? I suspect the use of flares or smoke rounds… well, it was my first impression…

    • “description text says the gun could be elevated to 90 degrees”
      According to query in Russian wikipedia, maximal elevation is 75°.

  4. Is that a suspension locking lever/bolt visible @ the 10:55 mark? It looks like you use that suspension handle to line up the chamfered locking bolt with a recess in the stub axle.

  5. I have read that one of the unexpected gaps in German military manufacture was that Krupp et al had great difficulty producing an interrupted-screw type breech; consequently the Germans used fixed ammunition up to an enormous scale.

    Using a fixed solid breech attached to the recoil mechanism, and a very simple barrel (easily replaced when the rifling wore out?) strikes me less as weird than good out-of-the-box simplification thinking, particularly as German breechblocks were usually of the sliding or flap type. In the context of fixed ammo, even on this smallish scale, makes perfect sense.

    Torsion-bar suspension had made itself very popular in the 1930s too: see the Volkswagen Beetle.

    • Not fixed but two-part ammunition with a brass case for the powder charge and a separate projectile. Fixed ammunition in artillery lingo means cartridge loading, that is, essentially like a scaled up rifle cartridge. Semi-fixed is loaded as a single unit, but the projectile can be separated and charge adjusted in the field. Fixed and semi-fixed were used by all nations up to 105 mm, because they are quicker to load than separate or bagged charge ammunition.

      The Germans by WW1 could have produced guns with a screw breech and bagged charges, but they chose not to, probably because the sliding breeches and two part ammunition was faster to load and more mature technology for them. It is notable that both the French and the Russians also made similar artillery pieces, even after WW1, despite both having access to mature interrupted screw designs.

    • There is quite a story (not explained to public for good part) of clash between an American company who was tasked to complete the project and H&K who were source of nitty-gritty knowhow. Recently they settled at court with the latter paying some ‘nominal’ penalty. It is probable that H&K has no interest in pursuing this concept due to liability.

  6. Oh… another excellent addition to small arms!
    What this is in reality, is breech loaded mortar. Very clever design indeed. At first look I’d think it is, due to its inventiveness, French.

  7. nice video. definitely include more of this stuff. i liked the parts where you showed the suspension and traverse. never knew it worked like that. now somebody restore and fire it!

  8. The current definition of “light weapon” includes cannon of caliber 100mm and less.

    https://en.wikipedia.org/wiki/Small_Arms_and_Light_Weapons

    Traditional infantry regiments (8 or 10 line companies) had an organic artillery battery of from two to six field artillery cannon. Custer’s 7th Cavalry had a pair of Gatling guns and a pair of 3-inch rifled field guns, both left behind when Custer did his Little Big Horn thing.

    I think that the 12cm mortar Germany encountered in French and Soviet hands displaced this infantry gun.
    https://en.wikipedia.org/wiki/Granatwerfer_42

    The 7.5cm light howitzer did have flat trajectory fire that wasn’t possible with the mortar and was probably more precise a weapon–but the 12cm mortar was lighter, could put down a greater volume and weight of explosive shells, had longer range, and was far cheaper to manufacture.

  9. There seems to be some confusion between “direct fire,” flat trajectory fire, “indirect fire” and high angle fire. I cringe whenever someone calls all 40mm grenade fire “indirect fire” simply because of the firing angle. Conversely, M16 rifle fire along a principle direction of fire as part of the final protective fires in a defensive perimeter using aiming stakes and with no visible target can be classed as “indirect fire” even though the 5.56mm NATO can deliver grazing fire from the muzzle to 600 meters.

    Direct fire refers to the launching of a projectile directly at a target within the line-of-sight of the firer.[1] The firing weapon must have a sighting device and an unobstructed view to the target, which means no objects or friendly units can be between it and the target. A weapon engaged in direct fire exposes itself to return fire from the target.[2] This is in contrast to indirect fire, which refers to firing a projectile on a ballistic trajectory or delivering munitions by guided or unguided missiles. Indirect fire does not need a direct line of sight to the target because the shots are normally directed by a forward observer. As such, indirect fire weapons can shoot over obstacles or friendly units and the weapons can be concealed from counter-battery fire.
    https://en.wikipedia.org/wiki/Direct_fire

    Compare that to indirect fire:
    NATO defines indirect fire as “Fire delivered at a target which cannot be seen by the aimer.”[1] The implication is that azimuth and/or elevation ‘aiming’ is done using instrumental methods. Hence indirect fire means applying ‘firing data’ to azimuth and elevation sights and laying these sights. Indirect fire can be used when the target is visible from the firing position. However, it is mostly used when the target is at longer range and invisible to the firer due to the terrain.
    https://en.wikipedia.org/wiki/Indirect_fire

    The 7.5cm le IG-18 has a gun shield because it is primarily a direct-fire weapon. Take a look at the maximum firing range, too–4000m, which is not quite to the visual horizon on flat ground. If the maximum firing range of the infantry gun was 10,000m and it had no gun shield, it wouldn’t be used for direct fire–in direct fire, the enemy can shoot you as well.

    • I don’t think it’s really accurate to say that the lIG 18 was primarily a direct fire weapon. The crews were well trained in indirect fire techniques and the ammunition had an adjustable powder charge (5 charges), which is really only needed for high angle indirect fire, where coarse range adjustment is done with the charge. Even more importantly, indirect fire was used in practice all the time. Range of 4,000 meters (actually 3,550-3,750 m depending on the source) was not bad by WW2 standards. For example 81mm mortars had a shorter maximum range.

      The included gun shield does tell us that the gun was indeed designed for direct fire in mind as well. It does not tell that indirect fire was clearly secondary and seldom used. Some guns used primarily for direct fire such as the Italian 65mm mountain gun (65/17 Mod. 13) omitted the shield for weight savings. On the other hand the Soviet 76mm ZiS-3 divisional gun had a shield, max range of no less thsn 13 km, and it was used for direct fire all the time, but also for indirect fire.

      • I would call it dual purpose, as being able both to deliver both direct and indirect fire.

        “Take a look at the maximum firing range, too–4000m, which is not quite to the visual horizon on flat ground”
        With all that notice that not all battles of WWII were fought on ideally flat ground and there were often cased that even at much shorter range you would encounter object blocking line-of-sight. Most obvious are mountain (cf. Unternehmen Marita), but other cases can be found too, both natural and man-made. Even relatively mild and low hills could block your line, forest could block your line even if clay is flat. Enemy could hide behind railway embankment and in urban environment there are often places reachable only by firing indirect.

    • Alan –
      Wrong. You are using two examples handpicked for your own argument, and you are wrong even then XD

      Direct fire and indirect fire is simple and obvious – direct fire requires the target to be within your line of sight and indirect fire requires that the target not be within your line of sight; ie: a flat trajectory projectile is incapable of hitting the target and therefore anything other than a high angle of fire weapon is capable of hitting the target; indirect fire at a target in a trench, behind a mountain, across the other side of city buildings.

      The Mk19 is a direct fire weapon out to 800 meters, because it fires a flat trajectory out to 800 meters. And beyond that, from 800 meters to the maximum range, the Mk19 can be used for indirect fire.

      Using aiming stakes in a fighting hole to fire at an area with with a 5.56 rifle is not indirect fire, it would be strategic fire out of line of sight.

      Some weapons are simply capable of direct fire and indirect fire and some are only capable of direct fire.

      You are simply wrong and wikipedia is a shit source. 😉

  10. Here’s official US Army doctrine on indirect versus direct fire:

    http://www.infantrydrills.com/fm-3-21-8-chapter-2-section-ii-weapon-and-munition-characteristics/

    Note that high trajectory weapons (ie, the 40mm grenade launcher) can be direct fire or “direct lay” weapons. Many flat-shooting weapons are indirect fire weapons–but the old 175mm gun has been out of service for a long time.

    This light howitzer was mostly used for “close support” and appears to be primarily for direct fire–with the gunner sighting in DIRECTLY on the target. I don’t know about the 15 cm gun–not detailed here.

    • + Alan –
      You wrote:
      “Here’s official US Army doctrine on indirect versus direct fire:

      http://www.infantrydrills.com/fm-3-21-8-chapter-2-section-ii-weapon-and-munition-characteristics/

      Note that high trajectory weapons (ie, the 40mm grenade launcher) can be direct fire or “direct lay” weapons. Many flat-shooting weapons are indirect fire weapons–but the old 175mm gun has been out of service for a long time.

      This light howitzer was mostly used for “close support” and appears to be primarily for direct fire–with the gunner sighting in DIRECTLY on the target. I don’t know about the 15 cm gun–not detailed here.”

      OK – you are not even making sense now. I do not think you even understand what you are trying to teach others. Instead of coming here as a student to learn, you came to argue as some professor uninvited. Dude, listen to these people, they know their shit. 😉

  11. @Alan

    AS I posted, that is I posted a primary source, they were used primarily for indirect fire. They didn’t get a chance to read a modern US Manual I guess?

    They were too valuable to push into positions that could fire back. They were the Regimental indirect fire weapons. The author, an officer in the 13th company, states as much.They were of limited value in a mobile attack/pursuit situation, and were also not very good in retreat since they were the first to pack up and leave.

  12. Also…The US had 105mm infantry guns in WWII. These were usually brought into the division control and fire plans. They were not very well suited for regimental control, and after WWII, they were dropped.

Leave a Reply

Your email address will not be published.


*