driving bands

[dano1917]

Pictured is a German WWI 9cm shrapnel shell with the Dopp Zc/91 fuze, that was a gift from one of our German members (the dopp Zc/91 was used only on 9cm shells explosive and shrapnel). My question is why two driving bands? Just seems a bit odd to me that they would use two bands.....Dano

 

[waffenamt]

Maybe the extra drive band gave a better 'fitting' up the spout? (less power loss and better stability?,as its a big shell!)
Not my usual bag but i thought i would give it a go!

cheers

waff

 

[beihan62]

Driving bands,

Hi Dano,I am just hazarding a guess here,would a shrapnel shell be a projectile that needed extra stability during firing to stop it tumbling due to it being filled with shrapnel balls and possibly a little out of balance balistically,or again just guessing,a thin driving band on a heavy shell so put another driving band to stop gas leakage during firing,I am assuming a normal artillery shell would not be as heavy as one that is filled with shrapnel plus a bursting charge,the lower driving band is very close to the base of the projectile,could this shell have been fired using a seperate bag charge as there does not seem to be much of the projectile for the neck of the shell case to grip,hope my bit of sideways thinking makes sense,
Kind Regards,Don,

 

[EODGUY]

Dano, I'd give three guesses on the extra band. First, in-bore stability of the projectile. The lower band is fairly small for the size of the projectile to be a single band. The forward band would stop any possible yaw during travel down the bore. Second, another obturator, or gas check seal to keep propellant gasses from escaping. Third, two smaller rotating bands should be easier to engage the rifling, possibly cause less in-bore drag, and not result in as much fouling as a single larger band. A student of the earlier projectile designs may offer a better explanation, but I have seen several different projectiles with the double band design over the years.

 

[Gspragge]

The upper band is common on early

37mm projectiles, and seems to be to limit wear on the bore (no iron on iron)
and mainly help centre the projectile while it goes up the bore, an additional
gas check maybe on larger projectiles, but it's kind of far forward for that
and a further rotation area to grip seem to be more of an early feature,
the later ones barely touch the lands judging by the very light indents
on them. Some modern projectiles have them. The 3"70cal I have
has one and that's from the 1970s, it has notches in it so it's definitely
not a gas check.

 

[dano1917]

straight shooter

Better stability makes sense to me. Does make me wonder why there were not more 2 driving band projectiles. Seems to me that it would be a little easier on the barrel wear too. Beside stability seems to me that the accuracy would be better also. The straighter a shell exits the barrel seems that it would affect stability and accuracy of shot. Anyway it makes for a cool projectile....Dano