12 mm Lentz Anti-Balloon Bullet, WW1


Recently on the WK2ammo Forum a forum member posted a good mechanical drawing (shown in both German and English) of the WW1 German 11 mm anti-balloon cartridge with the Lentz incendiary bullet, obtained from the German Federal Archives or Bundesarchiv. The complete drawing (dated 1914) and a computer rendering of a cartridge may be viewed here: ( wk2ammo.com/showthread.php?8 … ntz-Gescho )

Apparently the Lentz bullet works in the following manor: when the fired bullet exits the barrel two conical safety pins are thrown clear of the projectile, thus allowing the striker/firing pin to move upon impact. At impact the striker firing pin hits a primer which fires and ruptures a glass vial of acid. The acid interacts with an incendiary chemical composition causing an incendiary chemical reaction, which in theory would ignite the flammable gas of the enemy balloon.

If anyone can add to this or make corrections please do so.




From: Patronen für Hilfs- und Beutehandfeuerwaffen des Zeitraums 1914 bis 1938, Anhang 6 (appendix 6, pp 130 - 132), W. Micke; there is a brief discussion of the Lentz 12 mm bullet (12 mm is an assumption based on diagram in the post above) with pictures. The proper designation for the cartridge, based on the diagram, is Patrone 12 x 85mmR.

Below is a translation of some of the discussion/description of the Lentz bullet found on page 132. Forum member Alex a.k.a. EOD was a BIG help with this by correcting the Google translation from German to English so that it made sense. The text in italics is editorial comment based on input from Alex.

“As the diagram is indicating this is a 12x80R” (case length according to the diagram shown in post above is 85 mm) “cartridge basing on the M71 case” (11.15x60R).
“As already known this cartridge was fired from a bored out M71 Jägerbüchse” (a short carbine version of the M71 Mauser rifle, this one here was also named “Ballon-Gewehr”).

“A description was not provided but it is assumed that the striker in the proj. tip is driven into the priming composition when balloon fabric is hit which then is breaking the glass ampoule which contained acid that reacted with the incendiary composition and ignited the balloon’s gas filler (presumably Hydrogen). A real specimen of this cartridge is unknown to me and as it is unsafe to handle (who determined this?) it is unlikely that many have survived till today.”


As far as I know only the chamber of the M71 rifle was modified to accomodate the much longer case (holding the safety cones in place).
The bore itself remained the same.


This is perhaps a marginal matter, but the 71 Jaeger Buechse wasn’t really very short at all. I don’t have the figures before me, but I think it had a barrel of 29 in. or so, compared to the 33 in. of the true infantry rifle. In other words, it was far longer than the 18th century arm from which it derived its name. Jack


You are correct: Jägerbüchse 747 mm (29.4") barrel, ordinary rifle 855 mm (33.7").

Edit: I now found my notes. The source is a report on developments underway at Gewehr-Prüfungskommission when WW1 started. (Bundesarchiv file RH12-2/94)
It mentions the Lentz incendiary bullet for use agains gas-filled balloons. The glass body contained sulphuric acid.
The text indeed says it was fired from modified Jagerbüchse 71 rifles. [Maybe these were available by accident. I see no technical reason. JP] Range was limited to 600 m.

While I am at it, the other problems GPK was working on were:
Armor piercing bullet (SmK) with a tungsten-steel core. Penetration good, accuracy not.
Problems with long range sS bullet [sS at this early time!!!] due to its dispersion problems (larger than S bullet) because of difficulties of consistent boattail manufacture.
A longer, heavier S-bullet (12.8g) with straight(!) base, wich was intended to have much less muzzle flash for airship use. Did not have the desired effect.



Seeing what they thought up 100 years ago just blows my mind sometimes. Thank you gentlemen!



The original souce for the drawing shown in the first post is Bundesarchiv signature PH 24/469. It is dated 13 July 1914.

PH 24 contains a lot of very interesting drawings, among them some refering to a project for a 7 mm high power rifle, or a silenced Parabellum pistol. If you ever spend time in Freiburg, visit Bundesarchiv. (Get an appointment WELL in advance. If you are used to UK National Archive prompt service in Kew, embrace for a very different level of service.)


Here is a different example of a Lentz anti-baloon projectile found in a 1912 magazine.


Herewith a picture of the Lentz bullet.



Great picture! Thanks.