Bismarck 38cm artillery muzzle velocity

[alecsandros]

Hi,

I remember reading once that the 38cm guns mounted on Bismarck were slighlty modified versions of the initial version, and that their muzzle velocity was slightly higher than 820m/s (new gun).

Anyone know more about this ?

[Thorsten Wahl]

I posted that information

I could positively identify at least 4 versions (more or less identical) 38 cm SK C34
38 cm SK C 34
38 cm SK C 34e used by Bismarck
38 cm SK C/34f used by Tirpitz and
38 cm SK C/34 Siegfried Geschütz (coast artillery)

38 cm SK C34 /(e) and (f) wer basically identical except some(with small differences in barrel structure

38 cm SK C/34 propellant RP C/32 nitrolycerin based powder
main charge weight ~115 kg
for charge weight ~100 kg
~115 kg propellant

38 cm SK C/34e propellant RP C/32
Main charge weight ~108 kg
for charge weight ~102 kg
~110 kg propellant

desoite the reduced propellant and same lenght of projectile travel (16175 mm) the time for passing the barrel was reduced from 35,2 ms to 33,3 ms. Officially both guns had a muzzle velocity of 820m/s
maximum range was given with 35.6 km but the Baron von Müllenheim Rechberg wrote in his book that maximum range was 36.2 km
ther are two indications (traveltime and range) that possibly indicate for a moderate increase of muzzle velocity in the order of 15 - 20 m/s.


38 cm SK C/34 uses RP C/38 diethylenglycoldinitrate based powder
according ammunition regulkations main charge 108 kg
fore chrage 104 kg
somwhta more charge weigth in exchange for the reduced calorific value
RP C/38 produces a reduced flash and smoke

38 cm SK C/34 Siegfried uses Gu RP G5
Nitoguanidin based powder
Charge weight ~300 kg for lightweight projectile Vo 1050 m/s
Charge weight ~261 kg for 800 kg projectile Vo 820 m/s
this gun had a increased chamber volume

[alecsandros]

I posted that information
desoite the reduced propellant and same lenght of projectile travel (16175 mm) the time for passing the barrel was reduced from 35,2 ms to 33,3 ms. Officially both guns had a muzzle velocity of 820m/s
maximum range was given with 35.6 km but the Baron von Müllenheim Rechberg wrote in his book that maximum range was 36.2 km
ther are two indications (traveltime and range) that possibly indicate for a moderate increase of muzzle velocity in the order of 15 - 20 m/s.

If this would be so, this would imply the range tables and calculator programming on board Bismarck/Tirpitz would have been prepared accordingly ?

[Guest]

Hi there, I was wondering if you have any information as regards the MV of the coastal version with the full charge of the light projectile ( 300 kg ) but using the 800 kg shell instead of the 261kg used to attain 2690 fps for the 800 kg projectile. Also I would think the extended barrel life would be more due to the use of lower calorific charge than the use of lighter projectiles. I have recently come across a facinating article about tests conducted on German cannon after ww1. Their conclusion was the that the guns of that period used a much cooler burning charge and coupled with superior materials used by them at that time led to very extended barrel life. The example quotes of that period for the older 38cm 45 was that it could rack up 500 to 800 rounds. Very impressive but I wonder is there any further documentation out there that can help in this regard.

[Thorsten Wahl]

light shell was 495 kg
muzzle velocity 1050 m/s
version of the gun 38 cm SK C/34 e and f
propellants
-e R.P. 32
-f R.P. 38

maximum range 54,9 km (according british tabulation from fireeffect tables) at 53 degrees elevation (this is from memory i didnt find the source) using Bettungsschießgerüst
version of the gun 38 cm SK C/34 g (Siegfried gun)
propellant
- gG.R.P - G5
using the Bettungsschießgerüst the 800 kg projectiles had a range of 42,1 km

[Djoser]

The more I read about the 38 cm SK C34, the more I think this precision engineered naval rifle has been consistently underrated in the popular (allied) accounts of the war. Not that it was necessarily better than the extremely impressive US late model 16" gun--that was hard to beat by virtue of accurately delivered shell weight alone.

But imagine a fully worked up, crack gunnery team in Bismarck or Tirpitz finding the range and going into rapid fire on any contemporary ship you choose.

Anyway carry on with your more advanced technical discussion. I salute you all...

[Guest]

I totally agree. I also think that Bismarcks guns are underrated. I have also found published works ie navweaps which do not reflect the actual tested penetration values found in German documents. German documents show (Kdos 100) shows higher values against their own superior Kn ca armour, but for some reason have reduced values based on generic armour even though they claim that it's based on those exact documents. Maybe the operative word here is "based" allowing some license on the part of the authors to juggle the figures to fit a theory. Do they feel that it is too much and must rationilize it somehow? I would think the correct approach would be to try find out why the difference and not try and calculate it away. My own research would suggest a very advanced shell design but that another topic. I must say tested data IS tested data and is therefore a reflection of reality. No matter how good a theory is it is only proved by a real live test to see if the theory is any good. Basing ones assumptions on theory is at best useless and at worst misleading. Anyway I also wonder at the values given for the coastal batteries : new gun 3400 fps + , versus 3000 + for an average or worn gun. That is an excessive difference to say the least ( US guns would show only a 50 fps difference and I don't think that the Germans made worse guns )and if true would make accurate shooting well nigh impossible. I would like to see the actual documentation as what makes sense to me would be : 2690 fps for 260 ish kg propellant ( can't remember exact value ) - 3000 fps for 300 kg propellant , remember with 800 kg naval shell - then 3400 fps + for light shell. That makes a whole lot more sense to me as far as the coastal version is concerned.