How BBs are made

by B.B. Pelletier

This report was requested by blog reader Wulfraed in one of his comments.

For the benefit of those who shoot airsoft guns, the BB I am addressing today is the steel BB that historical BB guns shoot — not the 6mm plastic ball that Asian-made airsoft guns started using in the 1970s.

Brief history
The first BB used in an air rifle was BB-sized lead shot used by shotgunners. In the day when it was popular (the 1880s), shot was sold in bags in hardware stores and came in various numerical and letter sizes, including sizes B, BB and BBB. BB shot was supposed to be 0.180 inches in diameter and weigh more than nine grains.

At the turn of the 20th century, Daisy reduced the size of what they always called air rifle shot to a lead ball 0.175 inches in diameter. That saved them lead and also went faster because it was a lighter ball.

In the 1920s Daisy discovered that some boys in Minneapolis were using steel ball bearings that they were salvaging from a reject pile behind the American Ball Company. They checked the sizes of the balls they wanted to shoot by dropping them through the bores of their shot tubes. If they passed through, they were fired. If they stuck, well, a huge influx of stuck steel balls in shots tubes was what got Daisy’s attention in the first place.

Long story short, Daisy bought American Ball and started making their own steel air rifle shot. It was sized 0.171-0.173 inches, nominally. They had to change the size and design of their shot tubes to accommodate the new shot, and some time late in the 1920s BB began rebounding from hard targets with great force — something the soft lead balls had not done. This started the mothers of American warning against shooting your eye out.

Wulfraed’s question
So, how do they make a perfectly round sphere of steel? You can’t afford to cast steel into balls, nor can you afford to forge or swage the balls — again, because of economy.

So, how is it done? Pretty simply when you understand how it works.

Ever roll a piece of clay into a ball? You hold it between your palms and rotate each hand in the opposite direction. Has anyone not done this as a child?

So, short of being Superman, how do you roll a piece of steel into a ball? Well, it helps to have hands of steel, and that’s exactly how they do it.

The first step is to get a piece of steel that’s close to the right size, which means the same mass as the ball (BB) you wish to make. An easy way to do this is to take a spool of steel wire and cut it into precise chunks, then feed them between two hardened steel plates that have spiral grooves cut in their mating faces. Each plate is several feel across.


Each large spool of steel wire weighs about a ton (2,000 lbs.). These are fed into a precision wire cutter that slices off exact chunks the right size to make one steel BB. You can see by the amount of wire on hand that they intend making millions!

This wire-slicing process is called heading; and if it isn’t done precisely, the finished BB may be spherical, but have one or more small flat spots in its surface. This defect comes from improper heading and is very difficult to sort out during the manufacturing process.


This BB with a flat spot from a header error made it all the way through the manufacturing process. This used to be very common but is seen less often today.


BB on the left with three lead balls of different sizes. Copper-colored lead ball is plated with a thin coating of copper. Ball at right is .22-caliber size.

The plates are smooth on their surfaces, except for the spiral grooves. The chunks fall into the grooves as the two plates rotate in opposite directions — like your hands rolling a piece of clay into a ball. The spiral grooves catch the sharp edges of the cut steel pieces and roll them around as the plates turn. Once the pieces fall into a spiral, they cannot get back out, so they remain in the groove, tumbling and rolling around.

The spirals also become more shallow as they spiral in the plates, so the balls can’t stop tumbling and rolling, and they cannot back out. As the steel plates turn, the balls are forced in the same direction, which makes them smaller and rounder as they go. In the end, most of them roll into near-perfect spheres — just like the clay balls you rolled in your hands.

I would like to show you these steel plates; but this part of the BB-making process is considered proprietary, and I was not allowed to photograph it.

These balls are not yet BBs. But back to this rolling process a minute. The manufacturer feeds thousands of chunks of steel each hour into each set of plates they have working, and when the chunks are rolled into near-perfect balls, they then drop out of the plates. Some kinds of imperfect balls will also drop out, but they’ll be caught later on.

So, thousands of round balls per hour come from each set of rotating steel plates. The balls that exit each set of plates are carried by conveyor to a metal-plating machine where they receive a very thin coating of rust-inhibiting metal. As raw steel balls, they would start to rust almost immediately; but when uniformly plated with copper or zinc, the steel is sealed from the air and the BBs can last for years without oxidizing.

Once they’re plated, they’re sorted by several processes. One process rolls them down a spiral channel where the smooth BBs pick up speed and roll up on the sides of the channel from centrifugal force — much like a bobsled going downhill, while those that have some rough spots roll slower and more bumpily, staying in the center of the slide where they eventually drop through holes and are eliminated. What passes this test are finished BBs.

They may be graded by size at this point, by passing over holes of different sizes and then being sent to different places for packaging into different products. If any are too small or too large, or if they have any flashing or other imperfections, they’ll usually be caught in this last test.

Start to finish, the process takes some time, measured in hours because of queing and transit time. The actual manufacturing time is much less. Crosman runs three shifts a day and cranks out 4 million finished BBs every 24 hours.

Daisy used to make its BBs this way, or by a process that was very similar, but they have now moved the manufacture of their BBs offshore. They receive 55-gallon drums of finished BBs from their foreign manufacturer, which they then sort before packaging. Their BBs are extremely uniform, so the process works regardless of where the BBs are made.

27 thoughts on “How BBs are made


    • Bob,

      I don’t think so. Lead shot is now made by flinging droplets from a seive centrifugally into a pool of water. The tower cost too much to build, compared to the horizontal process.

      Large shot is swaged in dies, just like round balls.

      B.B.


      • Bob,

        I missed your first question. I have had air in scuba tanks for several years. I think they are like PCPs — you want them to be full all the time.

        B.B.


  1. B.B.
    Brings back memories of my boyhood days in Guyana. We used to roll 1/2″ (approx) clay balls in our hands then put them out in the sun for a few days to harden. Best slingshot ammunition I have ever used.
    Pete



  2. So a small nick in the plating exposes the steel and makes them rust so that’s why some of them oxide super fast but not others!

    I love to know how things are made.

    First day back to school for my daughter today, she’s starting 3rd grade… I feel old.

    J-F


    • JF: My youngest also starts third grade and I am 53 . His classmates think I’m grandpa with my grey beard. That will make VERY old .


      • Watching our kids growing up is a weird feeling.
        Beeing proud and a bit sad at the same because because they’re growing up to be nice kids but they’re not little kids anymore. You’re happy to see them being able to do more and more stuff by themselves and you’re less and less needed and a bit less important too.
        My daughter is really dad’s little girl and my son really is mommy’s little boy.
        I can’t wait to shoot with them and show them how to drive but at the same time I would want them to still my little babies forever.
        You how when you’re growing up how older people are always telling how good you’re having it and to enjoy it how you still can and how much things change as you get older and how fast time flies by as you age and you just look at them in disbelief and shrug it off and don’t believe a word they’re saying to realise later how painfully right they we’re? I’m having one of those moments right now.
        It’s no biggie but I’m kinda very happy and a little sad at the same time.

        Sorry for the long totally irrelevent post.

        J-F


        • JF: Not really irrelevant. I get it ,folks who have no children never will. I think that those of us who do, have a better understanding of our place in the scheme of things, and our own mortality.


        • Not to worry. Your kids will always be kids to you at any age. I’ve found that out with my elderly parents. I went home recently a mere shell of a man, walking on my cane, and with a couple weeks of TLC (and some prednisone) have emerged a new man. It wasn’t all the medication either.

          Matt61


      • I know the feeling Robert. Just turned 57 and my sons are 9 and 11. The 11 years old especially is willing to ‘jump to my defense’ when someone says something like…’you boys out with grandpa today’…he usually indignantly responds…’he’s my DAD’, and gives them a withering glare.
        Anyhoo…best thing in the world in my opinion is to have your kids later. I’ve way more patience now than when I was in my 20/30′s and I get to do all kinds of cools stuff (shooting, playing catch, going to inane movies, etc), that would normally get one accused of going through their second childhood.
        Hey…I gotta do it…it’s for my boys ;-)


  3. BB,
    I’m using UTG one piece mounts, and they do not center perfectly over the barrel. PA has a video on this issue and shows the benefits of using BKL mounts. When checking the PA web site for BKL mounts, I see they offer one with 24 minutes of fixed drop correction and one that offers 120 minutes of adjustable correction. Any experiences using this adjustable mounts? BKL mounts are expensive, but they look like a great way to perfectly center the scope to the barrel and also stay within a tight window of the scope’s optical center.





      • I was thinking shot tower. Can’t you heat the steel to molten form and put it in free fall? The temperature would be higher than for lead I’m guessing, but the process should be the same.

        Matt61


        • I think BB’s are too small, would cool too quickly for them to form perfect spheres before becoming solid. Molten lead (at a much, much, much lower temperature). There is a huge difference in the specific heat capacity of lead and steel. I don’t know what role that would play. I do know that molten lead is much less viscous than molten steel, lending itself to making the spherical transition much more quickly during free fall.


  4. I often wondered how bb’s were produced so cheaply. Hard ball bearings are ground, but that would be too expensive to just shoot. Now I know how it’s done! Thanks,BB!

    /Dave


  5. Fascinating. I was always terrible in art, and my clay creations were not things of beauty. But I can appreciate the process of creating a bb. How do you create a perfectly curved surface… And never underestimate your ball bearing. I understand that they are basic to very high technology. During the Cold War, some people got uptight because the U.S. was selling precision grinding machines overseas that could be used to create ball bearings for use in the guidance system for missiles. I expect that the tolerances were even tighter than the process above.

    In other news, airguns to the rescue. Apparently, an increase in garbage somewhere in South America has caused an explosion in the population of seagulls, and the birds are now feeding directly on the backs of whales when they come up for air! Outrageous. Airguns are being used on the seagulls. Maybe they should try the full auto version. Otherwise, I guess the whales could learn to breach explosively upward to knock the seagulls out of the way and then drag them down into the water if any caught hold.

    Matt61


    • Matt,

      Lead melts at very low temperatures. Steel is hot enough to melt terminators! I would be possible, but not recommended.

      The current way works fine.

      B.B.


    • Not using molten steel may also be a matter of economics – I imagine the cost of melting the steel to form BBs would add too much to the cost of production. Just a guess.

      Paul in Liberty County


  6. BB,
    D34P got in today. Pretty anticlimactic, so far. I actually still prefer the Blackhawk’s synthetic stock (Diana messed up on their improvements for the sake of style trend and almost let the forearm and buttstock get “serious airgun” chubby though not quite that bad), and Blackhawk seemed to shoot better out of the box (even if I detected a more certain choke in the Diana), although the Diana held its own at 10 yards with Superdomes and I’d been mowing a pasture so maybe a little tired at 25 yards :), but the Diana has sturdier looking sights and the T06 trigger is just a tiny bit better than the cloned T05 (no slip/creep at all in stage 2) — I wouldn’t pay for the difference in triggers by itself. The Diana is quite a bit twangier (not bad, but noticeable) and a bit harder to cock (likely due to 1 piece cocking lever vs. Rugers articulated lever), although the lockup is a little lighter (maybe PA lubed it). Nothing I can’t live with if it shoots straight (checked 25 pretty quick) and holds up a few thousand shots rather than 70! Anyway, some dude named Tom Gaylord “picked” this one (per PA catalog), so you might already know its pretty good. Much improved over the older 34/.22 a friend had, also, in terms of interface. To be fair, if I had time, I’d probably still try Blackhawks until I got one worth messing with, though — assuming the barrels aren’t all cockeyed; a good tune should fix any other problems.


  7. Fascinating report! Thanks, BB!

    Had enough strength today to drive myself for blood tests. A major advance. I really appreciate the reports on engineering details.

    –pz


    • Pete,

      Good to hear about your returning strength. You are in my daily prayers.

      I like the engineering details, as well, and as I think of them I will report them.

      B.B.


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