The importance of rifling

by Tom Gaylord
Writing as B.B. Pelletier

A history of airguns

This report covers:

  • Kentucky rifle
  • The smoothbore rifle
  • How accurate?
  • How I know
  • How they did it
  • The point

Reader Fido3030 inspired today’s report. He is intrigued with the accuracy of an unrifled BB gun — let’s use the Daisy 499 as an example. At close range we know that the 499 has accuracy that is unparalleled. The gun is made for the Daisy National BB gun Championships and is so accurate that other models don’t even compete. The competition distance is 5 meters, which is just over 16 feet. At that distance, this gun will keep all its BBs in the 10-ring of the target.

But increase the distance to 10 meters, which is twice as far, and the BBs start to open up. There is a limit to how far a round ball will remain accurate. Fido said he thought the ball was accurate because is equalized the air pressure on all sides, being smooth and spherical. That seems to be right for a short distance, but after the ball has flown farther it seems like the air starts working some mischief.

Kentucky rifle

I told Fido that the Kentucky rifle was what proved the value of spinning the ball. Daniel Boone is recorded to have intentionally hit a man in the head at 200 yards with a shot from his Kentucky rifle. Fido responded that he thought that many Kentucky rifles were smoothbores.

I’ve heard that the majority of Kentucky Rifles were actually smoothbore. In the woods they were accurate enough to hit a deer at the distances they could see one, but could also pattern a small load of shot. I think this is from the Dixie Catalog.

The reason you may have read this is because many of the old Kentucky rifles are smoothbores today because they were shot out. When that happened, it was common practice to bore them out smooth or to re-rifle the barrel to a larger caliber. Boring smooth was cheaper and a lot of the old guns became shotguns at that point. And that leads me to the next point.

The smoothbore rifle

Smoothbore rifle sounds like a contradiction in terms. Like a square circle. And the majority of people who use the term rifle today do not use it correctly, or even know what it means. They use it when they really mean long gun. A gun is not rifled — a rifle is. Does that make sense? But smoothbore rifles do exist. If the gun has a front and rear sight and if the barrel walls are thick, it probably started out as a rifle.

In the middle 1800s a group of shooters in Ohio was shooting at paper targets with smoothbores that had once been rifles. They were interested in seeing how accurate such guns could be.

The difference between a shotgun that was made to be a shotgun and a smoothbore that was once a rifle is the thickness of the barrel. Shotgun barrels are thin, where rifle barrels are thick. I have seen a rifle with a smooth bore that had a barrel of almost two inches in outside diameter. The walls of the barrel were over a half-inch thick at the muzzle! Not only did this gun start out as a rifle — it was an extremely heavy bench rifle made for target shooting only. But it was shot out and then bored smooth, turning it into a gun called a smoothbore rifle.

Nelcon Lewis muzzle
The muzzle of the Nelson Lewis combination gun shows the relative thickness of a rifle barrel (right) to a shotgun barrel. Even though the rifle bore is much smaller in diameter, the barrel walls are thicker to take the additional pressure of the powder charge, plus the ability to be re-rifled when it is shot out.

Kentucky rifles and the rifles that followed used a round ball inside a tight-fitting cloth patch. These patches wore the iron of the rifle barrels very fast. You might get 5,000 shots before the rifling was worn smooth. While that sounds like a lot compared to what a centerfire rifle gets today, it is nothing compared to what a rifle will get if it shoots lubricated lead bullets. They can get upwards of 30,000 shots, and rimfires that shoot lead bullets will get close to 100,000 shots before the barrel is worn out. So by comparison the patched barrel is rough on rifling.

Before patched balls, there was no rifling to watch, so nobody paid much attention to how many shots a gun could give. The wear-out rate was probably equivalent to that of rifled barrels, but it wasn’t talked about as much, as far as what I have read.

How accurate?

So how accurate were these smoothbore rifles? Well, it’s been at least 15 years since I read about the Ohio shooters and all my attempts at research have run into a dead end. I did find a guy on a muzzleloading forum who was claiming to put 5 round balls from a smoothbore into 2 inches at 50 yards today, so I would assume the shooters in Ohio were at least that good. They were probably better.

Out at 100 yards, though, the accuracy drops off. If they could shoot 5 shots into one inch at 50 yards they would probably be around 6 inches at 100 yards — that’s how much and how fast the accuracy drops off.

If I had another life to live I might get interested in testing this myself, but we are talking about years of shooting and it could all end in the knowledge that round balls that don’t spin lose accuracy at longer distances. I already know that, so I’m not interested in testing for it.

How I know

You see, I have tested this already — right here on the blog. I wrote a 5-part series on the Diana 25 smoothbore that showed the accuracy at 10 meters — which was great, and again at 25 yards where it was lousy. That was while shooting diabolo pellets instead of round balls, but in Part 5 of that report I did shoot it with Beeman Perfect Rounds, which are also H&N Rundkugel, and got a large group. So the pellets were more accurate than the round balls, even at close range. That’s how I know what I’m talking about.

How they did it

Those round ball shooters found that the ball had to fit the bore very tight to get the best accuracy. They also found that it did not pay to drive the balls very fast. Beyond that, I really can’t tell you much.

The point

The point is, I think it is an axiom that a round ball can only be accurate close to the gun. At some distance the balls will start to disperse and nothing can keep them from doing that. Balls that are spin-stabilized will be accurate to far greater distances because their spin equalizes any small imperfections in the ball.

53 thoughts on “The importance of rifling

  1. Thank you for taking the time to research and address questions that have been bothering me! I’ve about given up on trying to get an ordinary BB gun to perform like a 499-B!!
    By the way, have you found 499-B barrels to deteriorate after much shooting? Mine seems to, maybe I’m doing something wrong.
    Thank you again for your time! There is nowhere else that questions like this would be taken seriously!!!


    • Fido3030,

      I have a 499B and about 1/2 way through my (first) tub of 1050 of Avanti shot. How much have you shot yours to think that there may be a problem? Rested at 24′, it will do 20mm. avg. with 15mm. being the best I have ever got. That probably says more about me than the rifle though. 😉 The 24′ just happens to be what the indoor short range is set up at. I have yet to try it at the official 5 meters. The other option is the 41′ indoor “long” range. With winter here, I will have to give that a go as well. ( Matt61,…yea, my “man cave” is set up for function just perfect ). 😉


    • Have you looked through the barrel yet?
      If not please do so.
      I was thinking .177 was too small for dirt daggers to build a nest in but the discovery of a cocoon in my 160 shows that even the smaller .177 bore is not safe from these and other small vandals.


  2. Thanks to you Veterans! Dec. 7, 1941! To date all Veterans! I date my notes and started by writing the date and wrote Dec. 7, 1941? Then I scratch it out and put 2015! Sorry! Fellows I don’t think if it wasn’t for our Veterans we would be enjoying this blog! Yes, I think that’s right! Not to take away from B.B., the blog etc.! Semper fi!



    • My dad enlisted into the army on Dec. 8, 1941. He drove a tractor into Boulder, Co. to get to the recruiters office. He didn’t come back from Europe until the war there was over. If it wasn’t for him and 2 or 3 million others like him that fought for our freedoms ,we wouldn’t have been able to have the kind of life that we have today!
      B.B., you mentioned round balls in rifled barrels would be more accurate than in a smooth bore. Any way to determine how much the imparted stability will affect at ranges past what can be achieved in smooth bore? I guess I can answer my own question- just shoot them both. But does it really make a significant difference?
      Bruce


      • Bruce,

        Rifling does indeed make a significant difference. As BB pointed out, The Kentucky rifle was very accurate. I have seen tests of muskets (smoothbore) versus rifles from the Revolutionary War era. A musket was doing good to hit a man sized target at 100 yards while a rifle could hit a man in the chest at over 300 yards.

        There were two reasons why armies of the time used muskets instead of rifles. One was that the musket is faster and easier to reload than the rifle. You did not have to fight the friction of the rifling when you rammed your ball home. Most of the time they did not even use a patch.

        The other reason is cost. A smoothbore barrel is a whole lot cheaper to make than a rifled barrel. When you are talking about making thousands of barrels, that can be a most significant cost.


        • RR
          I was just sitting here wondering how, in those old days, they were able to mill a barrel for its whole length in a straight line when I realized that they didn’t have to! The last few inches would be all that determined the direction of travel and if you didn’t bend the barrel it would remain consistent. That is a new revelation to me!



      • Bruce,

        I should have added more detail to that remark. Round balls properly loaded are more accurate. As in patched balls. I don’t see that naked round balls are that much better at long distances than when shot from smoothbores.

        B.B.


        • If you use a slightly oversized cast lead ball does it conform into the rifling of an airgun enough to leave marking on the ball and would it have any signficant effect on velocity due to drag in the barrel?


  3. Interesting on the accuracy specs. I recall testing my Remington 870 with the rifle sighted smooth-bore 20 inch cop barrel and being surprised and gratified at its slug accuracy at 50 yards or so. At 100 yards the slug accuracy fell off somewhat…but as Frank Hamer used to say, “still accurate to at least ‘minute-of-Clyde’.”
    How accurate?
    About 2 inches at 50 yards, about 6 inches at 100.
    But still about as much as either my wallet and/or my shoulder could stand.


    • The most accurate slug load for smooth bore shotguns is the Federal Truball. It has a plastic ball at the base of the slug that expands the slug to match the bore. It’s a bit like the original French Minie Ball. It works.

      Mike



      • Mike,
        Thanks for the reply. As things happened, I blundered into a local gun store specializing in law-enforcement sales and they were moving upstate. They (wisely) realized moving biggish chunks of lead longish distances was not a completely rational idea so they kindly passed a pretty largish quantity at very (VERY) cheap prices on to me. That was at least 25 years ago and I’m still shooting slugs and .308 from that purchase. I’ll have to wait until I use the remaining supply up before I try anything new. By my reckoning, at my present rate, that should be in about 2062.
        I didn’t mean to start a science project on long-team storage for this sort of item, but so far, the flexible seals on the mid-sixties vintage cans are still good and whenever any of the contents are tried, I get a bang first time, every time.
        Can’t say I’ve any complaints…so far. (I just looked at the original recept. It was more like 30 years ago. Go Federal.)
        About the only complaint on the 870/slug shooting was from my (at that time) Security-Chica/Girl Friend who complained that the shooting “hurt her eyes.” Now this was a six-foot specimen that weighed maybe 93 pounds. She claimed a six mph breeze could lift her off the ground if she didn’t keep a brick in each hip pocket. I’d always thought every bone in her body was at risk from recoil, but no… The problem she said was, “Every time I shoot, my eyeballs pop entirely out of my head and when they snap back in, it really hurts. Makes me see stars, too.”


  4. Well RATS ! Looks like my goal of shooting a BB pistol at 10 meters and keeping all the shots within a 3″ sight N C target is not reasonable or feasible . I am looking forward in getting a bb gauge, when they are available. So far one of the most accurate bb pistols I have is the S&W 327 TRR . I can get maybe 4 out of the 6 into the 3 inch circle, but not consistantly . There is always the @#$$%^ flyers. Great read and Thanks BB. And yes I will remember this day as long as I live. I was a 4 year old kid and remember my mom crying when we heard the news on the radio.


  5. Chris, when new I could shoot 1/4 inch groups at 10 meters. After thousands of shots it is still excellent but not that good. Sorry can’t be more specific, it’s been a while. Or maybe it’s the nut holding the stock!!! Just curious about others’ experiences.


    • Fido3030,

      That is some fine shooting. I can see why you asked the question. The short pull of the 499 is an issue for me. I have a TX200 and LGU and added 1″ pull with Limbsaver re-coil pads,…so you can imagine what the 499 feels like. Thanks for the reply. Chris


  6. B.B.,

    It took a long time to learn a lot of what you’ve written above (some of it I just learned as I read it!)

    At a short enough distance, and 5 yards to 5 meters certainly is short enough, shooting a lead pellet through a rifled barrel has no advantage over a steel BB shot through a smoothbore barrel. Charles R. Ward’s tests of many CO2 rifled pellet shooters and smoothbore steel BB shooters at 5 yards demonstrates that. At that distance many of his BB guns outshoot many of his pellet guns. If he shot at 20 feet, I suspect the BBs would start to have notably bigger groups while the pellets would spread significantly less. At 25 feet you have many times showed quite dramatic differences in your tests. The several BB guns you tested at that range grouped much worse than the pellet guns you have tested at 10 meters.

    Michael


  7. Tried centering the Tasco Pronghorn 4×32 before mounting it back on the Remington Airmaster but have to mount it to get some stability, I couldn’t find a ghost image when I mounted it but I’ll be opening the back door after it warms up so I can get it dialed in again and use one of the 766’s to get the BB stop calibrated for .177 lead balls. I remember this setup taking a Grackle out at 75yds about a week after getting outta the hospital and one-handed at that, somewhere between there and 85-90 it starts running outta steam enough for hunting.
    Wonder what the second zero will wind up being if I dial it in for my new shorter range of 10yds?
    I’ll let y’all know when I find out but that’s a project for another day, today will be dialing in on my 10yd range.



      • I had started using 9.8 Winchester round noses almost exclusively in it when I got the Chrony but I took the Grackle with a CPHP @ 7.9. The only other pellets worth trying in it were 8.18 Stoeger match wadcutters, therefore the lightest it woulda been was 7.9.
        The only thing I did to it powerwise was seal the barrel and breechblock with shoe goo then lightly stroked the transfer port to ensure all was seated.however that was also 14 pumps, otherwise it’s stock powerwise.
        Other mods include a full length barrel stabilizer cut from nylon reinforced water supply line and pulling the BB stop so it would feed lead balls. I’d like to shave a little off the stop and get it reinstalled to cut down on double feeding.
        I pulled this gun outta the dumpster in 3 pieces one day after I had to walk the trash an extra block to find a dumpster, bought a 29¢ screw and but to put it back together with and never looked back.
        Whatta Deal!


        • Reb,

          That stuff right there,….that’s what I was talking about on how much you know and have done.

          The full length barrel stabilizer really got my attention. I assume that would be something that fills the void between the barrel and shroud? Maybe something to try on the 499 since the barrel comes out? Just an idea.


          • Yes, that one just May be perfect for the 499 although I can’t be certain because I’ve never seen inside one.
            The supply line I used required WD-40 lubrication to slide over the barrel and the shroud shaved a little off when it went on then I had to drill down to the barrel for the rear sight screws and forearm anchor.
            It was a project but it’s my go-to pumper ever since and solid as a rock!


          • The barrel shim di require full access to the barrel which I’m not sure is possible on the 499.
            While shooting the Airmaster with open sights I noticed the loading port door fluttering upon firing with 10 pumps so I haven’t got it totally sealed yet but also means there’s still more power to wring outta this platform, I’ve thought about an O-ring seal in front of of the plastic probe seal but I’ll try that one on one of these other guns before I strip the Airmaster down again. I’ve already sealed the 2200 magnum barrel/breechblock but still gotta get a bolt for it.


            • Reb,

              The 499 barrel comes right out from the muzzle end, along with the cap and a coupler nut that holds the 2 together. The tuff part would be getting/finding the right ID and OD tubing.

              On custom shimming, when putting the muzzle weights in on the LGU, I wrapped masking tape around the OD, about 1 wrap, to bring it up to the right OD. Worked well and very solid. The same idea could be applied to a barrel and shroud set up. And, instead of doing a full tube on the barrel, you could do a series of “rings” that would accomplish the same thing.

              The 499 does not put out much power but I thought your idea was still interesting.


  8. I was gonna go to the office to get a HIpac on order for my 2240 while it warms up ou but it’s closed. My 3rd inspection for the past 30 days is finally complete.
    Almost feel as though I’ve been institutionalized.
    :/


  9. B.B.
    I remember shooting steel bbs in my old smooth bore 760 at some wild birds which were trying to get into my chicken pen.
    The distance was 50 yds + and in the morning light I could see the bbs going Down range in an ever increasing spiral. I guess the loose fitting BB would impact the side of the barrel at a different point each time before exiting the muzzle causing the spiral to begin at a different point with each shot. This might be why a loose fitting bb(ball) is inaccurate as the distance to target increases.
    Pete


  10. Given that airgun barrels should last for centuries, I was wondering what could wear down rifling in firearms so fast. Odd that the cloth patch does more damage than lead, but I’ll take the evidence for what it is. On the subject of bullet spin, the effects of spin on a pointed projectile, while intuitive, are somewhat murky in detail. But exactly how spin enhances the flight of a round ball is completely mysterious to me. Anyway, whatever the accuracy limit of smoothbores, I doubt they reach the claim of one guy at a blackpowder workshop who said that he could shoot two inch groups standing at 150 yards.

    Gunfun1, I had supposed that laser intensity was due entirely to the size of the powerplant. So, perhaps the green lasers that reach 100 yards are only for rifle-size lasers that wouldn’t fit on a pistol. Maybe that explains why my tiny micro laser is so weak. But that’s odd how different versions of the same brand performed so differently for you. It looks like the green laser will just be for dry-firing around the house which is mostly what I use the gun for anyway and where the laser is very bright.

    I’ve also rethought my opinion of the CZ 75 after more examination last night. I see that by inserting more of my finger into the trigger, the alignment problem disappears. Mindful of good technique, I was pressing more towards the point of the finger which puts my finger at a sharper angle to the trigger. As for the trigger pull, is there such a thing as a three stage trigger? I pull through the first stage until resistance. Then when I exert more pressure, there is more movement until the shot breaks. I don’t know if this is a bad trigger or just a different design. Perhaps this is a modification for tactical purposes. The information is that the CZ 75 SP-01 was designed for military and law enforcement. In tactical situations, you would not want the tuned triggers of my other guns. Since I already have fine triggers, perhaps it would be worthwhile to learn a tactical trigger. Also shooting great David Tubb says that part of shooting skill is the ability to master almost any kind of trigger. So, I just might take this as a challenge.

    Matt61


  11. Got a receipt number for a HIpac and 1 extension to offer a little more flexibility to this build. No phone number posted to confirm which is disconcerting especially since they dropped my last order in someone else’s box.
    When the receipt page pulled up it had a place for special instructions but there was no way to enter them.
    I wish they’d finally finish that site!


  12. Got a email from HIpac saying that 2240 models were already on backorder so it would be another week or something to that effect.
    I responded by stating that the time to put that on the website is probably before someone places an order and to notify me of any changes in status as my last order wound up in someone else’s box and I’d prefer to keep a closer eye on this one.


    • Got a generic response restating what the first one said without addressing any of my issues and almost had PayPal cancel the order. This guy’s testing what’s left of my patience.
      I had hoped to get a QB-78 and use this setup but I can’t see doing business like this.


      • Got cut off by a text from my assistant saying she wouldn’t be able to make it again tomorrow, after taking her mother to Abilene today instead of coming here to work her son now has an emergency doctor’s appointment tomorrow.
        I’ve tried explaining that if she wants the job then she has to show up but it looks like I’ll be calling Girling tomorrow morning to get this fixed.
        Definitely a Monday!
        “Self destruct countdown commencing!”


  13. Cloth and paper patches wearing a barrel out? I must ask,….is there not any barrels that are made with hard enough steel that they won’t wear out,..regardless of what is put through them? Maybe an obvious answer to a well schooled powder burner, but not to an airgunner such as myself.



    • Chris,

      First you need to remember that we are talking about guns that were made over 100 years ago. Their barrels had different metals than we have today. They were made soft so it was possible to rifle them with hand tools.

      Next, consider that firearm barrels are not made hard even today. Sometimes they do get work-hardened as they are made, but that’s about it. They rely on metallurgy to last — not hardness.

      Third consider the pace of a muzzleloader. They don’t shoot rapid-fire. And these kind of guns are not normally used for plinking. A gun might shoot 5-10 shots a week or even a month, depending on the circumstances. So they took years and decades to wear out. The pace was different then.

      B.B.


      • B.B.,

        Thank you for the education. That is something that I really knew (and still know) little about. When water can carve rock,….I guess that anything is on the table…… Chris


  14. BB,

    I remember being at the 50th anniversary of the Pearl Harbor attack. It was a ceremony held at Pierre, SD. Members of the Pearl Harbor Survivors Association were there, some of whom I had seen on the History Channel.
    A flag that had flown over the Arizona was flying. The survivors were still stung with sadness.

    I also remember a conversation I had in a barber shop in Pierre with a sailor from the Oklahoma. He told me he had left the Navy shortly before the Pearl Harbor attack. He told me about a training cruise he had taken on the ship during the Spanish Civil war. There was a gun battle between a British ship and a Spanish fort. Shells from both sides were arcing over the Oklahoma.

    He said the Oklahoma was a good assignment. Plenty of room on the battleship, good food: plenty of fresh fruits and vegetables. He like to go to the engine room while the ship was underway and watch the vertical triple-expansion engines work. He said he always felt very safe on the Oklahoma due to its heavy armor and large size.
    He added with extreme sadness that 400 of his shipmates were killed that morning.

    We can read about these events, and watch films, but until you visit in person with a person who actually experienced these things, it isn’t quite real. I will never forget these experiences. It made the event quite real to me in a personal sense. I will never forget it.

    Les


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