US Artillery in WWII: 105mm firing rate

[Yoozername]

http://www.criticalpast.com/video/65675 ... om-the-net

I remember some online 'discussions' regarding the firing rates of the 25 pdr. and the US 105mm howitzer. Clearly, the video shows a firing rate that the 25 pdr, or any seperate projectile/charge system can not achieve.

Hopefully PC4 can model the actual 'quick-fire' that some weapons could achieve. This did come at a price. The US not only ran short of 105 ammunition, they also burnt out tubes very quickly.

[Mobius]

People make the mistake of using the indirect firing rate of some guns as the rate that would be used in their anti-tank mode. With targeting, tracking, obscurance slowing down the rate.

[Yoozername]

That's true.  The M7's are clearly firing indirect and there is hardly time to even look through the sight.  The loader seems to be the limiting factor.  I doubt this rapid-fire can be held up for more than a dozen rounds before human or gun factors play in.
 
Tanks firing direct at long range would initially have to observe the fall of the shot.  The weapon might be reloaded before the first shot is observed, the sight corrected and the next round is fired. 

[Yoozername]

If you look closely at the 88mm firing in videos, it appears there is an oscillation of the barrel in the ground fire role (when the barrell is parallel to the ground).  This would certainly have to dampen out if there was to be accurate long range AT fire.  Its very noticeable at the end of this video.
 
http://www.youtube.com/watch?v=sElNyLusnNU&NR=1

[Ratzki]

It looked as though the barrel movement appears in all positions, but more when parallel to the ground. I think that target re-aquisition after recoil would give enough time for this movement to stop. It appears on the video to calm down quickly after firing. It might be needed somewhat for accuracy. I know that rifle barrels vibrate during bullet travel down the length of the barrel and afterwards. It has to do this or accuracy would be extremely reduced. This is why you float a barrel, to allow for the movement and why traditional long stalked guns like was used during the war are not very accurate, then put a bayonet on the gun and you might as well not even aim at all.
Just a thought.

[freeboy]

well, perhaps we should define accurate.. for the hunter hitingthe elk at 350 yards is awesome, for the competitive shooter 1000 yard tight groups are the goal.
The german 88 in anti tank role was very accurate, plus 2000 meters, from the anti tank gun or turretted versions... if you are looking for a cold to hot barrell calc and the goal is to put a round on a tank at 1000 -2000 then accuracy to me would be hitting it...
 

[Yoozername]

http://www.youtube.com/embed/MasHown9MH4

These 88s are certainly pushing it. They are helped by a auto-eject of spent rounds.

[Ratzki]

ORIGINAL: freeboy

well, perhaps we should define accurate.. for the hunter hitingthe elk at 350 yards is awesome, for the competitive shooter 1000 yard tight groups are the goal.
The german 88 in anti tank role was very accurate, plus 2000 meters, from the anti tank gun or turretted versions... if you are looking for a cold to hot barrell calc and the goal is to put a round on a tank at 1000 -2000 then accuracy to me would be hitting it...

I am not saying that the 88 was not accurate, I am just noting that the long barrel might need the movement to keep it accurate at range. I thought that the discussion had moved to rates of fire and the 88's barrel movement after firing. I am not talking about hot/cold barrels either, but the movement all barrels have during projectile movement down the length of the barrel. Floating the barrel in a gun definately improves the hot/cold barrel warp from firing shell after shell, but it also helps by allowing the barrel to vibrate freely each and every shot. If viewed from a high speed camera, the gun barrels vibrate and move quite a bit as the projectile moves down and exits the end of the barrel. All barrels vibrate after they have fired. All barrels have to be "tuned" to the calibre being used. This is done in a number of ways from barrel length to barrel wall thickness, and others. Then once this "tuning" is found, the barrels can be mass produced to the same specs. I was thinking that an 88 is way bigger then anything I have ever seen shot so maybe this vibration/movement was needed to keep the round from tumbling or exiting the barrel off target. I thought that exponentially moving from a small calibre to a very large one might part explain why a better recoil system was not in place to help prevent this barrel movement in the 88. First it is a huge round and the projectile is moving fast enough that I would dare say that there is no moss growing on it along the way. It must generate a huge amount of recoil. I know that they must have had the ability to reduce this recoil, but as Yoozer pointed out, recoil is not only there but the barrel has this gyrating wobble as well. Would this affect the rate of fire? I wonder... maybe it was not an issue as the guy targetting the 88 would have to get off the first shot, then judging by the video clips, the target would probably have to be totally re-aquired as this gun kicks as hard as any and could be way off target for a second follow-up shot, by the time he is able to lock in on the target again this wobble is gone and is no longer an issue.

[Yoozername]

I would think the 88, when firing at near vertical elevations (AA) would not exhibit this obviously unwanted angular motion.  Mostly because gravity is not effecting the long parallel hanging off like a beam.  'Accuracy' is not that much of an issue when shooting AA.  88s would fire into a 'box' and the fleet of bombers would have to keep formation and fly through it.
 
When firing AT, I would almost guartantee that angular motion seen in the videos is going to change the range of the high velocity shot.  It needs to dampen out before the next round.  And that second video shows some fast firing. 
 
I have also seen video of the 88s firing indirect as artillery and the rounds are being fired at something like every 3 seconds.  Again, if the barrel does not stop moving, the angular change would translate into a large spread of HE rounds.
 
I remember a discussion I had with rexford and he was stating that the 88 had greater dispersion than he would expect.  I believe we came to a conclusion that its 'accuracy' fame was because the crews had good range-finders so they could take the range-estimation error out of the equation.  They had a great rate of fire and therefore could get hits and the impression of accuracy.

[Hellmann]

All I'm going to say in response to that is, my grandfather was a German tanker, and I would like nothing more than to see the Yoozername losername moron's head exploded by an 88 shell.

[Yoozername]

ORIGINAL: Hellmann

All I'm going to say in response to that is, my grandfather was a German tanker, and I would like nothing more than to see the Yoozername losername moron's head exploded by an 88 shell.

OHHHHH YEEEAAAHHHH??? My grandmother made Lt. Colonel in the Coast Guard reserves and she would scrape you off like a barnacle...

[Hellmann]

OHHHHH YEEEAAAHHHH??? My grandmother made Lt. Colonel in the Coast Guard reserves and she would scrape you off like a barnacle...

Thing is, I didn't say what he would've done to you. I just said I'd like to see him make mincemeat of a coward like you. So, somehow your grandmother is in the picture now? Seems like everyone else is in the frame now except your sorry ass self? Ah yes... how convenient.....

[Yoozername]

 
I think you have taken the 'Asshat-of-the-Week' award.  Congrats. 

And who said the Germans don't have a sense of humor?

[Hellmann]

I am German, so YOU are the "asshat of the week/month/year", congrats!

[Yoozername]

I would have never have guessed...

[Hellmann]

ORIGINAL: Yoozername

I would have never have guessed...

Indeed, same as I would have never guessed you were an asshat.......

[Yoozername]

Is this your granpa? I would hate for a comic-book hero to make me into mincemeat...

[Hellmann]

ORIGINAL: Yoozername

Is this your granpa? I would hate for a comic-book hero to make me into mincemeat...

Funnily enough... no a comic book cartoon isn't actually my grandfather... surprise surprise... but if you would prefer, I'd make you into mincemeat anytime you like by meeting me? Oh wait.. you can't actually do that? Oh dear, what a shame... what a little coward you are, for all to see...

[Yoozername]

Sure. Where do you live?

[Mad Russian]

Guys, this is going nowhere. We need to get back to the topic at hand.

Good Hunting.

MR