Bismarck Abkomm- & Kaliberschießen

[Ulrich Rudofsky]

In translating the Bismarck and Prinz Eugen war diaries I was not sure about the terms: Abkommschießen and Kaliberschießen.
There is an interesting discussion about this at: http://forum-marinearchiv.de/smf/index.php?topic=6441

1. Abkommschießen is firing with reduced caliber barrels. The 38 cm was reduced to 8.8 cm with an "Abkommrohr", a reduction barrel. This was done to protect the actual barrel from wear and tear and to save money.

2. Kaliberschießen is firing with the full caliber and a reduced charge. Apparently this was also done to protect the "Rohrseele", "barrel's soul".

3. There was a third type of practice firing where a rifle was fitted into the 38 cm and fired at towed metal "Klingscheiben", "ding-ding targets". This was used for training gunnery personnel in operation of the guns.

Question: What did these sub-caliber barrel inserts and shells look like?

[José M. Rico]

Question: What did these sub-caliber barrel inserts and shells look like?

I would like to know that as well Ulrich.

I checked "Schlachtschiff Bismarck Artillerie-Munitions-Übersicht" to see if there was any information about the practice reduced charges and shells but I found nothing.

I am wondering what would be the muzzle velocity of 8.8-cm shells fired from the big 38-cm guns.

[Tiornu]

I am skeptical. How much would a barrel insert weigh? Can this be a misunderstanding for the usual, externally mounted sub-caliber gun?

[Ulrich Rudofsky]

@ Jose

"Schlachtschiff Bismarck Artillerie-Munitions-Übersicht"

That is a very interesting document, but it refers to the combat loading inventory of the ship. The AVKS report clearly refers to "Abkommschießen" or sub-caliber firing, but I have translated "Kaliberschießen" as caliber or full caliber firing.......that is wrong! In the KTB and AVKS report were ever it says "Kaliberschießen", i.e., caliber or full caliber firing that should read: caliber firing with reduced charge. Ouch!

I would guess that the "Abkommmunition" and "Abkommrohre" were unloaded before the ship sailed on its mission.

PS: I wonder if the 8.8 cm was Flak ammo or something special?

[Ulrich Rudofsky]

An "Abkommkanone" a gun with an insert to reduce its bore diameter with a gun barrel insert. Is there such a thing in the USN?

"ein Geschützeinsatzrohr von kleinstem Kaliber, wird in Rohre großen Kalibers der Küsten- und Schiffsartillerie so ein gesetzt, daß die Seelenachsen beider zusammenfallen. Zweck ist, bei Richtübungen die kostspieligere Munition zu sparen".

"it is a gun barrel insert of the smallest [smaller?] caliber, and it is inserted into the barrels of the large caliber coastal and ship's artillery in order to "collapse" [reduce] the "Seelenachse", f-axis of the gun's bore (?). The purpose is to save on more expensive ammunition during alignment exercises."

http://hometown.aol.de/marineakademie/M ... _1905y.htm

[José M. Rico]

OK, Ulrich.
I will check the KTB as soon as possible and correct that.

By the way, Müllenheim-Rechberg mentions this on his book as well:

Practice firings served to train the gunlayers in the best way of keeping on target. These drills could be carried out satisfactorily at close range with 8.8- or 5-centimeter subcaliber guns inserted into the barrels of the heavy and medium guns. Because the shells and powder charges used were relatively light, this kind of firing was economical. At the same time, it gave the gunnery officers practice in fire control.

Check the German version to see the original wording and terms used.

[tommy303]

http://i63.photobucket.com/albums/h130/ ... eround.jpg

In this foto there is a sub calibre round on the spent cartridge tray on the left of the gun. It is 8,8cm and for the 28cm gun. I do not have a picture of the actual subcalibre gun itself.

[Ulrich Rudofsky]

@tommy303

Thank you for the nice photo

It appears that, according to my initial source at Marine Archiv, sub-caliber firing with barrel inserts is still used by the German Navy. The Lütjens Class 127 mm G3 gun used 7.62 mm for sub-caliber firing as practice rounds.