Rifling twist in Artillery cannons

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Iron Worker, Nov 15, 2011.

  1. Iron Worker

    Iron Worker Well-Known Member

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    Any one have a guess what the rifling rate was in a Sherman tank of WW2 was it 5R ? Button rifled or Cut rifled ?
     
  2. Bart B

    Bart B Well-Known Member

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    Most tank's main gun barrels were rifled with a 1 in 15 to 1 in 20 calibers. A caliber being the bore diameter. Field artillery barrels had about the same twist. Compared to battleship main battery barrels from 12 to 16 inch bores with a 1 in 20 to 1 in 25, they're pretty fast. But a battleship's 2000 to 3000 pound, 6-foot long projectiles didn't need to be spun so fast; they spin stabilized very well at a slower twist.

    Virtually all millitary large caliber barrels were broach rifled. A single pass of the hydraulic operated rifling machine was all it took. Some were made by a single-point cutter that made several passes in each groove which took a long time.

    6 inch and larger naval gun barrels had their rifling in a liner that, when worn out, would be pushed out its back end then replaced with another liner. 'Twas much cheaper and faster than replacing the entire barrel. I don't know of any tank or artillery barrels that used liners.
     

  3. Kevin Thomas

    Kevin Thomas Well-Known Member

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    Iron Worker,

    Okay, I'm curious; how did this one come up?
     
  4. Iron Worker

    Iron Worker Well-Known Member

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    That was very interesting ! Thanks
     
  5. Iron Worker

    Iron Worker Well-Known Member

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    We who buy custom bbls are particular as to twist rate and method of rifling installation . I watch the Military Channel a bunch,they had a special on tanks. So just curious as to their bbl specs .
     
  6. dogdinger

    dogdinger Writers Guild

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    I am pretty sure that i saw the new 120mm tubes on the Abrams main battle tank are smooth bore. I guess the sabot rounds they fire are self stableizing?
     
  7. Kevin Thomas

    Kevin Thomas Well-Known Member

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    Dogdinger,

    They're fin stabilized. APFSDS is the usual designation, standing for Armor Piercing, Fin Stabilized, Discarding Sabot. And yes, you're absolutley correct; they're smoothbores.
     
  8. Bart B

    Bart B Well-Known Member

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    There was a project in the US Navy during the late '60's to make the center gun in one or two battleship 16-inch gun turrets a smooth bore barrel. It would shoot Rocket Assisted Projectiles 100 plus miles. None was ever prototyped as far as I know, but something similar is covered in the link below:

    Super High Altitude Research Project - Wikipedia, the free encyclopedia
     
  9. Kevin Thomas

    Kevin Thomas Well-Known Member

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    Bart,

    Last time I was there, they still had one of Gerald Bull's HARP barrels out on the test range. As described, it was fabricated by joining two 50 caliber 16" gun barrels end to end. I took a pretty close look at it, but the muzzle was taped and sealed. I have no idea whether these were rifled or smooth bored, but it was a hell of a project. Some interesting stuff there.
     
  10. Kevin Thomas

    Kevin Thomas Well-Known Member

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    Iron Worker,

    there's actually some fascinating details concerning the development of US tanks at that period, and the gun systems were really only a minor part of the story. There were some major misunderstandings as to what tanks were going to be asked to do on the ETO battlefields. Very interesting stuff, but if you're interested, you might want to read Death Traps, by Belton Cooper. Cooper was an ordnance recovery officer during the Normandy campaign, charged with recovering and refurbishing (when possible) the knocked out Shermans. He has some very caustic comments for G.S. Patton and several others who were involved in choosing the gun systems mounted in early US tanks. Good read, I'm sure you'd enjoy it.
     
  11. Trickymissfit

    Trickymissfit Well-Known Member

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    there was also a project involving the 8" guns on a heavy cruiser that used a projo that was probably a third longer than a standard round (maybe longer), and a powder charge that looked like it was close to 50% larger. They claimed 35 miles with it! I do know that one of those cruisers parked itself right outside Hia Phong Harbor and shot the place to pieces. The shape of the projo was very much like a typical VLD of today, but the driving bands were made very differently if you look at the round very closely. There were two distinct driving bands that were not brass, and were actually part of the round itself.

    gary
     
  12. Trickymissfit

    Trickymissfit Well-Known Member

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    wasn't it Mr. Cooper who said the hardest thing he ever say on an Allied tank was the 75mm gun used on a Panther

    The Germans had several anti tank cannons of different calibers, and more than one are very interesting. There was one smoother rifle that used a tungsten cored anti tank round that had a tapered barrel! The barrel shrank from 88mm down to 50mm, and velocities were a little under 5,000fps. There are a couple photos of them being used on the eastern front and in the streets of Berlin. That 50mm Sabot was said to be able to crack the hull of any tank on the planet with ease. There was also a similar looking piece that used a 128mm round that had over 2000 meters of effective range, and was known to have penetrated the glaciest plate out front and exited thru the deisel engine out back! Then there was the generic 75mm PAK 40 that was only about 40" tall. Could drill a hole thru just about anything with ease. Russians had deep respect with anything that started out with the letters PAK! That particular anti tank rifle held the long distance one shot kill record till Desert Storm (3300 yards on a KV1)
    gary
     
  13. Bart B

    Bart B Well-Known Member

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    For readers, those 50 caliber 16" barrels were 800 inches long; 16 x 50 bore diameters. Almost 67 feet long.
     
  14. Kevin Thomas

    Kevin Thomas Well-Known Member

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    The German 75mmL/70 used on the Panther was one of the best anti tank guns used in the war, and was a threat to virtually any armor on the battlefield. Same round that was used in the PAK40 you mentioned as well, and quite different than the 75mm used on the PzKpfwIVs and Stugs throughout most of the war. Don't recall that specific quote from Cooper, but it sounds like something he said, or certainly would agree with. He was pretty bitter about the Sherman's performance in battle against the Panthers. I know of at least one instance where two(2) Shermans were taken out by one round from a Panther, the projectile passing cleanly through the first, and going on to penetrate the second Sherman behind it. That's some pretty impressive penetration in anyones book!

    The taper bore guns you mentioned were the Gerlich series. They never really came to fruition, at least never to the claims that Gerlich made for them. Speer eventually got pretty fed up with him over the hype and lack of real results, a dangerous thing in Nazi Germany of that era. After the war, Gerlich got some attention by the US Army Ordnace Corps, but again, his results never quite reached the results that he claimed they would. Still, he came up with some pretty impressive performance for guns of that time. Still, as you said, by the time the Russians hit Berlin, the Germans were throwing everything they had (including the kitchen sink) at them. That was one helluva battle, and the city still bears some of the scars.