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How are shotgun barrels made

Discussion in 'Uncategorized Threads' started by School Teacher, Feb 3, 2008.

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  1. School Teacher

    School Teacher Well-Known Member

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    How are shotgun barrels made? Are they simply a billet of steel that has been drilled out or are they a billet of steel that has somehow forced over a die to create a tube. I was asked this in a classroom the other day and I did not have an answer.

    I know that the older” twist” barrels were made by bending a thin strip of metal over a rod and then welding the spaces between the turns shut. This type of barrel is no longer made and is dangerous to shoot.

    How were the older naval guns, like the 16” guns on the battleships made?

    What is the difference between a barrel on a mass produced shotgun and the barrel on a custom gun like a Kolar?
     
  2. blizzard

    blizzard Active Member

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    The "older" barrels you refer to are Damascus twist. The "welding" you refer to used in their production is actually hammer welding, which is truly a lost art.
     
  3. Capt. Morgan

    Capt. Morgan TS Member

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    Shotgun barrels start out as a solid bar of chrome moly steel ("gun steel"). The bore is drilled in the center of the bar by a gun drill that rotates the bar instead of the drill. The outside of the bar is then machined to create the chamber and the fixed choke, which actually starts out as a slight bulge on the end of the barrel. The end of the barrel is then swagged between rollers to force the extra metal inward to form the choke. The inside of the barrel and chamber are then honed to final diameter and polished before external features are added.

    Morgan
     
  4. GunDr

    GunDr Well-Known Member

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    Some are also hammer forged on a mandrel, like Remington BBl's.
     
  5. phirel

    phirel TS Member

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    I think hammer forging is more common than the use of gun drills. It is very difficult to drill a long straight hole.

    Pat Ireland
     
  6. jakearoo

    jakearoo Active Member

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    Pat, Are you sure about that? I was not aware that many shotgun barrels were hammer forged. I thought they had been drilling them ever since they invented "fluid steel" billets abound the turn of the 19th century. To my knowledge, it was the method of compressing molten steel as it cooled that made the steel solid and hard enough to become gun barrels.

    If they are now being hammer forged, I would be interested in knowing where that is being done and what companies use those barrels. Jake
     
  7. GunDr

    GunDr Well-Known Member

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    I don't know many manufacturers that swedge OR weld their bbl's to the mono-bock. Most are silver soldered and a least one was/is held with a Loc-Tite product.

    I have on only two occassions, seen the bbl's pull out of the mono-block while shooting them. One was a Beretta and the other was a Valmet. Niether gun showed any damage, other than the seperation. Both guns showed a very dirty joint and poor soldering.

    Just a quick note about 90-T bbl's....After the bbl's were soldered into the mono-blocks, they were sent out and X-Rayed to check for a solid joint. All would come back at near 90% plus. Much higher than the 50-75% Remington requested.

    Doug
     
  8. oleolliedawg

    oleolliedawg Banned User Banned TS Supporters

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    All the 175mm. gun barrels that I had a hand in production back in the 60's were forged at Beth. Steel!!
     
  9. jlb

    jlb Member

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    John Wilkes http://www.finefirearms.com/john_wilkes.html makes one piece barrels. Thus both barrels are made, as I understand the process, from one piece of steel. I don't think that any other maker uses this process.
     
  10. jlb

    jlb Member

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    John Wilkes http://www.finefirearms.com/john_wilkes.html makes one piece barrels. Thus both barrels are made, as I understand the process, from one piece of steel. I don't think that any other maker uses this process.
     
  11. jlb

    jlb Member

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    John Wilkes http://www.finefirearms.com/john_wilkes.html makes one piece barrels. Thus both barrels are made, as I understand the process, from one piece of steel. I don't think that any other maker uses this process.
     
  12. pendennis

    pendennis Well-Known Member

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    To the best of my knowledge, naval guns were always forged, although some were cast in the early days, especially prior to breech loaders. Naval guns were often sleeved, when the outer gun was heated, and a new lining was driven in. A friend of our family worked at the old Naval Ordnance Station in Louisville, Kenturcky. He told me that the guns were reworked at some of the larger steel companies, and then shipped there for final machining and testing.

    Just outside of Louisville, the Knob Creek Shooting Range, where the largest machine gun shoot in the world is held in April and October, is site of the old testing range. 5" and 8" Guns were mounted on rail cars, and test-fired. The layout of the land there is testimony to the testing that went on there during, and right after WWII.

    Best,
    Dennis
     
  13. phirel

    phirel TS Member

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    Jake- I have seen rotary hammer forging of barrels at the Winchester and Remington plants. I do not know about any other companies. I have only seen one "gun-drill". That was at the Bendix experimental machine shop in LA. My first Father-In-Law was in charge of that shop. The gun-drill was not used to make gun barrels. I was told that it could drill a straight hole 40 inches long but it took so much time and was so difficult to use properly that the shop considered the drill as useless. I could have bought the drill rather cheap but it was about 9 feet long and weighed 3,500 pounds. It has a 20 HP electric motor that could be geared down to less than 1 RPM.

    O/T - The experimental machine shop fascinated me in 1967. When I visited, I watched a machinist making a hydraulic valve that was about 1/8 inch long and 1/16 inch wide. Drilling holes using a microscope and bits about as thick as a human hair was neat. My Father in Law also told me that he expected computer driven tool machines to eventually replace the experimental shop. I miss the fine hand craftsmanship of yesterday.

    Pat Ireland
     
  14. Roger IL

    Roger IL TS Member

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    Pat, I do not know if shotgun barrels are drilled, but nearly all rifle barrels are drilled with a deep hole or "gun" drill. They are then cut rifled, button rifled, or hammer rifled. Most all require straightening after they are rifled. I see no reason a shotgun barrel could not be drilled and hammer forged or button forged to size. Maybe the large I.D. of the shotgun barrel is a factor?.......Roger
     
  15. shotgunpeople

    shotgunpeople Active Member

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    I hope this thread continues. I find it rather interesting. Thanks School Teacher for asking this question. The answers here are something I have often wondered about but never knew.

    Dave in NY
     
  16. AveragEd

    AveragEd Well-Known Member

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    I believe the Discovery Channel had a documentary on Kreighoff a couple of years ago and part of that program covered how they make their barrels. I never was able to watch that episode but I read a lot of comments on here about it and it would probably be worth your while to see if you could obtain a copy.

    Ed
     
  17. GunDr

    GunDr Well-Known Member

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    Many years ago, I read a bok on the manufacturing of the Parker. Those bbl's were drilled. It was kind of funny when the guy wrote that particular chapter. He said that there was constant profanity coming from the bbl drilling area of the shop. Apparently, a gun drill would decide to go out the side of a bbl.
     
  18. timb99

    timb99 Well-Known Member

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    Found this in an article in Clay Shooting USA, specific to Antonio Zoli shotgun barrels:

    "The quality of shotguns tends to stand or fall by the quality of the barrels. At Zoli, barrels start life as steel bars, cut into 3 ft lengths and precision drilled, then polished by a reamer that is pulled through the barrel. Each tube is then put on a lathe to cut the outside profile of the barrel. A center-less grinding machine is used to ensure that every tube is identical; tolerances are to within +/- 4 ten-thousandths of an inch.

    Finally they are honed inside and out to achieve the final bore size and finish. For fixed chokes, cold swaging is used to achieve the required choke. The tubes are then inserted into the monobloc and carefully aligned – an area where precision is imperative."
     
  19. old tex

    old tex TS Member

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    Regarding Alfermann "Twin".

    According to Larry Alfermann they start with a round billet of 4140(I believe) 4 in. in dia.

    They stress relieve the billet.

    They mill it square and drill the bores from both ends, they discard all that don't "meet" in the middle to unbelieveably tight tolerances - all of the barrels, breech, lugs for forend and even posts for the rib are made this way -one piece of precision steel that shoot to exactly the same point of impact.

    AMAZING guns made by amazing craftsmen who don't just accept the "status quo".

    I own #14.
     
  20. code5coupe

    code5coupe Member

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    At one time, I asked Ruger about the barrel on my RRL, and they told me their shotgun barrels are hammer-forged.
     
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