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how do they make barrels?

Discussion in 'Gunsmithing and Repairs' started by cpileri, Jun 26, 2003.

  1. cpileri

    cpileri Well-Known Member

    more specifically, how do they make the bore so that it is in alignment with the barrel wall?

    i.e. if you have a round bar (cylinder), what tool/drill is used to core out the bore to be sure it is coaxial with the round bar?

    or, what is the name of the device used to make sure the hole goes straight through?

  2. Bruce in West Oz

    Bruce in West Oz Well-Known Member

    AFAIK, the barrel is drilled by rotating the barrel around the stationary drill bit. Once the hole is made -- and I'm simplifying here -- the bore is used as the centre and the barrel turned on a lathe, so the outside is turned parallel to the bore -- thus the hole is guaranteed to be "down the middle". Easy!
  3. Dave P

    Dave P Well-Known Member


    Try this site:

  4. JohnBT

    JohnBT Well-Known Member

  5. mete

    mete Well-Known Member

    There is no "guarentee" that the hole will be in the center. First there is a drill bit that is used to drill long straight holes, it's called a gun drill. The standard helical drill wants to drill a helical hole so the gun drill, which has a single straight flute, is used. Maany rifle barrels today start out as a 12" blank ,they are drilled then swedged to a 24" barrel. If great care is taken the hole will be straight and centered - if not it won't be accurate.
  6. Solinvictus70

    Solinvictus70 Well-Known Member

    Thanks for posting the informative links!! :D I've been curious about the making of barrels as well.
  7. 4v50 Gary

    4v50 Gary Moderator Staff Member

    Cold hammer forge

    Ruger has four of them (maybe six now) and Remington has some too. The factory that Kalashnikov works in has 30 of them.

    Basically they start with round bar stock (hole drilled) that is placed into a cold hammer forge. Four hammers begin hammering on the exterior and in so doing, the bar stock lenthens out as it is worked around the mandrel. The interior forms arounds the mandrel which imparts the lands & grooves.

    It makes for a very accurate barrel and is gaining in popularity not just in Europe (where we buy our cold hammer forges from) but also here.

    If you ever go by The Log Cabin Shop in Lodi, Ohio, or the NMLRA museum in Friendship, IN or Springfield Armory in Springfield, MA, you'll see examples of the old style rifling machines that entails a pull through cutter. Unlike the Cold Hammer Forge that makes a barrel in a matter of minutes (look at the target model heavy barrel Ruger 10/22 for an example), the older hand rifling devices takes about a day (pull through, brush off chips, oil and pull through again and again...).

    Now, there's a third method and that's EDM (Electro Discharge Material - sic) that entails controlled bombardment of electrons to chip away to create the groove, leaving the land to stand out. S&W uses this to make their pistol barrels.
  8. mete

    mete Well-Known Member

    4v50Gary, I was not aware that EDM(electro-discharge-machining) was used for barrels. The process is about 40 years old. It is not a process of bombarding with electrons . Instead the electrolytic process which takes place in a fluid , actually vaporizes the steel. It's an interesting processs , I used it years ago to drill .005" holes in steel !!
  9. 4v50 Gary

    4v50 Gary Moderator Staff Member

    Was told two years ago that EDM was developed by the Russians. S&W is the only Co. I'm aware of that uses it for bbl mfg. Ruger does it old fashion. Rem has hammer forges.

    I'd like to visit that wizard of barrels, Bobby Hoyt in PA. He's well known in the BP community. You want something relined, he'll do it. Right now he has a 4" S&W bbl that needs to be bored out and relined for my brother's friend. Would love to see his shop.

    Should mention that the one at Friendship is the Brockway rifling machine. It's more advanced than the old ones used by the gunsmiths of 1700-1800s. They allowed me to play (supervised of course) with it for about an hour. Too bad you can't buy a barrel blank and rifle it right there (takes about 1 day's labor). I've suggested it as a means of fundraising for the NMLRA.
  10. Jim K

    Jim K Well-Known Member

    Bobby Hoyt's shop is decidedly not high tech. Just good machines and highly skilled craftsmanship.

  11. 4v50 Gary

    4v50 Gary Moderator Staff Member

    You've been there Jim? Wow. Love to go there myself some day. From ultramodern (S&W, Ruger) to low tech. I love it all. A rifling machine isn't hard to build (booklets are common in the black powder community) and if I had the space, you betcha I'd build one and start rifling blanks. Eliphalet Remington had his barrel blank done and figured it wasn't much either way back in the early 1800s.
  12. Jim K

    Jim K Well-Known Member

    I was at the German festival at Kutztown, PA on Saturday. Not really much to see but they did have a old time gunsmith setup there, with the guy doing some actual work. He had a rifling machine (the old kind made of wood), but was not using it. He was working on a trigger at the stage where it is just a rectangular piece of steel with one side heated and dented in. I said something about a trigger and I think he was a bit surprised to find someone who knew what it was going to be.

  13. Jim K

    Jim K Well-Known Member

    One short note, on cpileri's original question about how the bore is made to go straight through perfectly centered. The answer is that it doesn't always. I have had occasion to cut factory barrels by some of the big companies, and guess what? Sometimes the hole is centered at both ends and not the middle. I had one customer who got so fed up trying to get a zero that he had us put on a new barrel. After studying the old one, I decided to cut it about the mid point. Sure enough, the hole was off center in the middle so bad that the barrel wall was less than 1/16 inch on one side. And that was a major company with their premium rifle! I have seen several .22 barrels the same way, also major makers.

  14. 4v50 Gary

    4v50 Gary Moderator Staff Member

    The old timers use to look down the bore to see how the light is casted. If it was tweaked, the would hammer it to straighten it. I've read about one fellow who would whack the barrel against the tree until he got it right. :eek: Other barrel makers made a bow and would run the string down the barrel to see if it was straight. Later, a barrel straightener was developed that featured a clamp and an overhead wheel. You clamped the barrel in and tweaked it with the wheel, all the time looking down the bore. This tool can still be seen in some gun factories today. I think there's one at Springfield Armory National Historic Site, but it's been a couple of years since I've been there.

    Like Jim mentioned, sometimes the modern barrel makers still don't get it right. One of them (John Getz) sells his scrap barrels to Beaver Bill Keefer (Mich or OH) who chops them into 5-6" lenghts and then forges them into tomahawk heads. Bill's hawk heads go from $200 to $300, depending on how much filing you want.

    Should have posted here but a weekend of or so ago the Log Cabin Shop in Lodi, Ohio had two days of barrel rifling demonstration (older style wood rifling machine).

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