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Education / Training What is a bull barrel?

What is a bull barrel?

by Tom Gaylord, a.k.a. B.B. Pelletier

A couple weeks back, a reader asked what bull barrels are. I said I would answer him with a report, and today’s the day.

what is a bull barrel

Okay — it’s history time. Remember when you were surprised to learn that the monkey wrench was actually invented by a man by the name of Charles Moncky? Turned out to be a huge 19th century urban legend, didn’t it? Well, the bull barrel was perhaps first popularized by Freeman R. Bull, a machinist and employee of the Springfield Armory in the late 1800s. Mr. Bull was a noted sharpshooter who excelled at offhand shooting, which made him one of the rock stars of the day. Springfield Armory used him often to test various prototype rifles because they knew he would give them the best possible evaluation.

In 1887 the armory made a special long-range Trapdoor just for Mr. Bull. It had a heavy octagonal barrel that was stiffer than the normal, round long-range rifle barrel they had been making. Getting 80 grains of black powder into the short 45-70 case was a real trick that required careful handloading and eventually led to the case being lengthened, but only for long-range target use. This was never a production military cartridge. But Bull’s rifle was a real shooter. He advocated using heavy barrels to cut down on muzzle movement when holding offhand.

Mr. Bull successfully shot his prototype rifle at great distance, but he was always standing in the long shadows cast by both the Remington Rolling Block and Sharps rifles that preceded the long-range Trapdoor by many years. During the last quarter of the 19th century, the government was engaged in a continual marketing campaign to prove that the 1873 Springfield single-shot had been a great choice for arming soldiers (despite the debacle at the Little Big Horn), not unlike what they’ve done with the M16. But, in the end, the bolt-action repeating Mauser in the hands of Spanish forces in Cuba put the nails in the coffin of the old Trapdoor. They soldiered on in the ranks of various National Guard units until the end of World War I, but their time as serious first-line military weapons was at an end by the middle 1890s.

So, was Freeman Bull the inventor of the bull barrel? Probably not. The barrel of his rifle was heavy, but it was octagonal, and bull barrels are uniformly round. The popular thinking is that bull barrels get their name from their oversized dimensions, as in “as stout as a bull.” If you go on various AR chat forums and websites, you’ll see discussions about what the differences are between bull barrels and heavy barrels, but that boils down to how many angels can dance on the head of a pin. Bull barrel and heavy barrel are 2 names for the same thing. What throws the AR shooters is that there is a specification for a heavy barrel for an AR-15/M16, and they mistakenly think it applies to all other firearms.

AR-15 bull barrel
This barrel is sold as an AR-15 bull barrel. It has flutes, but they’re not a requirement for a bull barrel. An AR heavy barrel would be much thinner than this.

So what exactly is a bull barrel on a rifle?

There’s no exact specification for a bull barrel. In fact, the modifiers “bull” and “heavy” can be used interchangeably. If there’s a distinction when 2 barrels are being compared, the bull barrel would be even thicker than the heavy barrel, but that argument quickly becomes difficult to resolve.

Bull barrels in firearms
Being thick, a bull barrel can absorb a lot of heat energy during firing, and therefore it heats up slower than a thin or standard barrel. It also vibrates less because the sheer bulk of the barrel absorbs a lot of the smaller vibrations. The result of these two factors is improved accuracy, but only when the barrel is rifled carefully. When someone makes a bull barrel, they do take great care in rifling it, so it’s almost a given that bull barrels will be accurate. Their extra bulk just adds to the potential.

10-22 bull barrel with standard barrel
The Butler Creek barrel on the left is sold as a Ruger 10-22 bull barrel. It’s heavier than the standard 10-22 barrel on the right but could also be considered a heavy barrel.

I see some places on the internet where bull barrels are described as having flutes. Flutes are grooves on the outside of the barrel that lighten the weight without taking away any of the stiffness. But flutes are not a requirement of a bull barrel, as these websites imply. They’re just one additional feature that the finer bull barrels can have.

What does a bull barrel do?
Bull barrels do several things that help accuracy. First, all the extra metal does make them stiffer and less prone to vibrate. Every bullet comes out the muzzle with the barrel in the same place, more or less. That’s the artillery hold at work, so a bull barrel tends to give the same benefits and get similar accuracy improvement.

The second thing bull barrels do is maintain an even temperature during firing. Since metal expands when hot, maintaining an even temperature keeps the barrel from changing dimensions, which promotes consistency from shot to shot. Consistency means accuracy.

A third benefit of a bull barrel is associated with its weight. Being heavy, it tends to allow the rifle to recoil less, and that helps the shooter cope more effectively. This is especially important when talking about the larger calibers that kick a lot.

A final benefit is also associated with the bull barrel’s weight. It pushes the balance point of the rifle toward the muzzle. Many offhand shooters find this helps them hold their rifles still.

What about airguns?
Airguns can have very heavy barrels that might be called bull barrels. The vibration damping benefit will be the same as for firearms, but heat dissipation is not needed because airguns don’t heat up when fired. The recoil damping benefit is valid for spring guns, which is where the majority of airgun bull barrels are to be found. In fact, many target spring guns of the 1950s through the 1970s had optional heavy steel barrel jackets that could be slid over the regular barrel to give a bull barrel look and benefit.

Walther LGV Olympia barrel
Walther LGV Olympia target rifle has a heavy steel barrel jacket, held on by a special nut at the muzzle. This turns the LGV barrel into a bull barrel.

But plastic is no good! Some spring gun manufacturers are covering thin steel barrels with thick plastic sleeves and calling them bull barrels. They certainly look the part, but they lack the real benefits of genuine bull barrels. Oh, they probably do shoot better than they would if just the thin rifled steel tube were exposed because the plastic does attenuate the vibration patterns to some extent. But they’re not true bull barrels.

Gamo Bull Whisper barrel
Gamo’s Bone Collector Bull Whisper IGT rifle barrel is a bull barrel in name, alone. Plastic around a thin steel tube does not meet the requirements of a true bull barrel.

Bull barrel facts
1. There is no specification for a bull barrel.
2. Bull barrels are synonymous with heavy barrels (except in specific cases).
3. A bull barrel made of plastic is mostly for show.
4. Bull barrels tend to be more accurate, as long as they are well-made.
5. Bull barrels add weight to the gun that may help stabilize it for offhand shooting.
6. Bull barrels add weight to the rifle and may dampen recoil.

So, look for bull barrels if you like, but know what they are and what benefits they bring to airguns.

author avatar
Tom Gaylord (B.B. Pelletier)
Tom Gaylord, also known as B.B. Pelletier, provides expert insights to airgunners all over the world on behalf of Pyramyd AIR. He has earned the title The Godfather of Airguns™ for his contributions to the industry, spending many years with AirForce Airguns and starting magazines dedicated to the sport such as Airgun Illustrated.

63 thoughts on “What is a bull barrel?”

  1. My Savage 93 .17hmr has A bull barrel.
    I really never knew how they got their name but I thought it was because of the size of the barrel.

    When a bull barrel is offered in a fire arm I will get it with that option always. I like the idea of the heavier weight at the muzzle end. Among the other things BB mentioned.

    I wonder if a person that was new to airguns and they seen a Marauder for the first time if they would associate the shrouded barrel to a bull barrel. Kind of like you explained about the Gamo guns but in a different aspect. No kind of way is the Marauder a bull barrel.

    Didn’t Dennis Q. make a air rifle that that was a combination pcp and pump assisted air gun in the past with a bull barrel. If I remember right it was in the .300 diameter cal. class. And I think he made a even bigger .400 and something cal. gun in that design.

    BB you know Dennis and I’m sure the different guns he made. But am I remembering right about the above DQ guns?

  2. B.B.,

    Discovering and knowing the origins of words and names has long been a fascination of mine, so I read this report with great interest.

    Also, I have several 10 meter springers, each of which, save an FWB 300s Jr., is outfitted with a bull barrel sleeve. As I tend to shoot seated with the rifle resting on my arm or bag and not off-hand, the weight helps some, but not as much as it might. I find that I shoot my 300sJr. just as well from a seated position as I do my FWB 150, which weighs 2 pounds more, most of it in the barrel sleeve.

    Even though I do not hunt, I also own, only because I was able to purchase it new for a song when it was closed out, a Gamo SOCOM Hunter Extreme. Unlike many other Gamos, this one has a Bull barrel that is a thick, heavy metal sleeve over a steel barrel. I assume Gamo chose to do that to reduce the chances of the barrel bending as an owner went through the effort to cock the thing.

    I have developed a technique for cocking that rifle which makes it quite easy, at least for me, because I weigh a lot and am able to leverage that into the process. I stand upright, place the butt of the rifle on the top of my shoe, lock the elbow of my left arm (as I’m a lefty), and with my right hand tightly grip the forestock near the linkage. I simply bend forward at the waist, holding the stock in place as my locked arm and heavy torso push the barrel down with my left hand at the muzzle until it catches. The thick barrel end and heft of the sleeve do help quite a bit in the process, or at least it feels to me that that is the case.

    That air rifle is one of the most powerful springers ever produced, yet it fires more calmly than do other springers I’ve shot with much less power. For one, it’s about 10 pounds, and two, that heavy barrel doesn’t jump. It moves up maybe a quarter inch with each rested shot, but I doubt if it’s more than that. With an extreme artillery hold and the forestock resting on the back of my knuckles resting on a bag, I get very tight groups at 25 yards.

    My SOCOM Extreme is quite accurate, shooting Eun Jin 16.9 grain pellets to keep it from going supersonic. Every now and then I’ll take it into the backyard to make a 2 litre bottle of pre-shaken soda pop (diet is the best as it’s the fizziest) explode. It’s fun to do little kid stuff like that every now and then!


  3. Besides lightening the barrel, the flutes provide more surface for heat dissipation. In recent years I have seen barrels with the flutes spiraling around the barrel. Supposedly this aids in cooling as the air is drawn over the barrel from the venture effect when it is fired. It also is supposedly more rigid than the straight flutes. Probably the biggest benefit of the spiral flute is the “Cool” factor.

  4. B.B.
    I bought the extra 24″ barrel for my Tall on SS and found it to be a thicker wall construction and heavier then the 12″ (both in .22 cal). Would this be considered a bull barrel?
    Thanks Lou

  5. BB,
    I agree that there is no difference b/t “bull” and “heavy” barrel, except possibly in the mind of the person who chooses one term over the other. For example, I tend to use the term “bull barrel” for a barrel that is relatively short (under a yard long most of the time is short to me, but that varies by application) and heavy, making it look very heavy. I’m not saying this is correct, just pointing out what might be a possible distinction in my usage choice, although I don’t know if even that is consistent.

    What is the justification for saying that bull barrels are always round? I’ve never heard that, and would consider the octagonal barrels on heavy ML’ing bench rifles, for example, to be bull barrels, and I’m pretty sure I’ve heard the term used by others in that context and similar.

    The name Bull very likely had nothing to do with bull barrels — I would guess that it had more to do with the male ego (we all have them) and identifying with the size, power and “virility” of bulls, much as we use “stud” sometimes. I know this is a family website, so I won’t take my barnyard philology any farther, but I will point out that we lose many obvious associations and metaphors over time as society changes and adapts to other situations.

    • While not researched, my mental image is that a bull barrel is /uniform/ from receiver to muzzle. A heavy barrel could still contain a taper from receiver to muzzle, albeit not as much as the “regular/light” barrel.

      Of course, I also consider the barrel on my Ruger Mk-II* to be a bull barrel, even with the slab sides.

      * the confusing nomenclature of Government Competition Target Model; various sides are marked with various parts of that string, and the model number, when compared to others, also tends to imply the string…

      • That is a good definition. I am tempted to call my Savage MkII BV a bull barrel. I am inclined to believe your definition of heavy barrel also — in my mind “heavy barrel” is one that does have taper, just not as much as as a sporter barrel, and probably is thicker at the breech than the sporter also.

  6. I was going to ask if gamo’s bull barrels are just cheap imitations but i see you answered this as a yes they are cheap imitation. When I came back to airgunning much more serious after my divorce I was impressed by Gamo’s guns. Now that I have aged and learned more about what is out there I’m kind of seeing Gamo guns as not such a great gun. The ones I now own I rarely ever touch now. I keep them simply as collector pieces. The Viper express was after all the first air shotgun I had ever seen. The Gamo Whisper was also the first gun I had seen of it’s kind. Now I keep it because anything with a shrouded barrel is so hard to get in Michigan.

  7. Walther LGV Olympia target rifle has a heavy steel barrel jacket, held on by a special nut at the muzzle. This turns the LGV barrel into a bull barrel.

    In a way, it does something else too, based on the look…

    The sleeve is being held in compression while the barrel, proper, is under (stretch) tension. That may provide more of an effect than merely a thick walled barrel… Similar to the old Dan Wesson revolvers with interchangeable barrels and shrouds.

  8. B.B.,

    Until I got my Ruger Mk II back in the 80’s, I had never heard the term “Bull Barrel”. The more common term (at least for small-bore target rifles) was “Heavy Barrel”. Now I see “Bull Barrel” used quite a bit.

    I am one of those who prefers the heavier barrels for stability reasons. In fact, I also added weights to my target rifles.


  9. Years ago I belonged to a rifle club and the old guy who had a Winchester model 70 competition rifle called it a “bull gun” . It did have the large diameter barrel/bull barrel.

  10. BB if I remember right it was in this book.

    The practical guide to airgun hunting By Jim Chapman. I believe the second edition. It has been sometime since I read it. And I don’t have it right now to look at.

    Maybe it wasn’t one of Dennis’ guns. But I’m pretty sure it was. It was a longer gun like a Kentucky long gone. And it maybe even had a octagon barrel if I remember right.

    Wish I had the book now. We moved to where we live at now and I never bothered unpacking everything. I will try to locate it though.

      • You are probably right about who made the gun. I would like to see a picture of the gun made by Tom Jones to see if it looks like what I remember.

        But anyway I thought that was a good idea of having a pump assist to back up the pcp. And if I remember right the pump handle folded out under the barrel and it only needed a few pumps to get the pressure back up. Real efficient design.

          • Yep I know who Tom Jones the singer is for sure.

            I really need to start proof reading my comments before I post for sure.

            But I found the book. The practical guide to air gun hunting.

            The gun was a ANA Quigley. I must of associated the two names and thought it was a gun made by DAQ.
            And the ANA Quigly is considered a pump gun from what I can tell. Not a pcp with a pump assist.
            Either way whatever you want to call it. I thought it was a cool gun.

            Well another mystery solved. 🙂

  11. Evening B.B.,

    I thought a bull barrel was what the Rodeo Clown dove into. Actually, I’ve got to agree with Robert. In the early sixties a bull barrel was a large diameter minimally tapered barrel seen primarily on bench rest rifles and some varmint rifles.


  12. Off topic: Does anyone know a decent pellet seating tool, or an easy way to make one? I have begun shooting my first break barrel (after being a PCP and Pneumatic guy for decades), and found that I really need to seat the pellets to improve shot to shot consistency. I purchased a pellet pen with the break barrel, but was cheap and got the one without a pellet seat tool on it, regret that now. I’ve been using a metal punch as it was about the right shape and works well, except for controlling how far to seat the pellets. Any tips on where to find or make one? Thanks.

    • Hi, Bristolview. The Air Venturi Pellet Pen and Seater has an adjustable depth seating tool:


      B.B. has commented on it in a blog or two. I don’t use one myself since all of my rifles use probes and such, but I’ve seen it and fiddled with it many times in person, and it seems a quality piece!


      • GenghisJan – Yeah that’s the one I referred to in my post. It’s about twice the cost of the pellet pens without the pellet seater, and I was cheap and didn’t opt for it (getting the cheaper one). All of my previous rifles all have a probe that pushes the pellet in when the breach is closed, so I didn’t realize how important it is when I got this break barrel. I should’ve opted for the one you linked to, my mistake. Now, I get to make one instead – and John’s suggestion above should work perfectly.

  13. Mr. Gaylord, in reference to your experiment with solid led bullets, have you seen the rather fascinating data on the “piledriver” pellets being made in the U.K. If they are accurate(?) i think they may well be the most promising advancement in solid led airgun bullets. I hope you and Edith are well. Thank you for your wonderful blog.

    • Pop’s SLR,

      I have tested the Piledriver pellets and found them to not be accurate. They are also nearly impossible to load. Too many mistakes were made by their makers of that solid pellet/bullet for it to be worthy of further testing.



  14. This is off topic. And I guess its ok to post this.

    I was just checking to see if PA got any Condor SS’ yet.

    They now show a .25 cal. blue one in stock and a black .177 cal. also. I have been waiting and thought maybe other people would be interested also.

  15. B.B., I have a new RWS 350, five weeks, about 2000 pellets shot. I believe the spring is broken. It will not engage and catch in trigger assembly. Have you known of a spring breaking this soon? Have changed spring in a BFS 55N several times. Any thoughts? Should I do this myself or send back?

    Thanks Baldred

    • I’m having difficulty seeing how a broken mainspring would affect the latching of the piston by the trigger/sear assembly.

      The cocking lever, to my understanding (and simplified), catches a ledge on the piston, and pushes the piston toward the rear until the sear latches onto a similar ridge.

      A broken mainspring could mean the piston is not under pressure for part of that movement (if the break results in a net length shorter than the nominal stroke length) or could maybe bind the cocking action, stopping the stroke short (say part of the spring is catching the outside/rear of the piston, rather than being compressed inside the piston). Either condition would seem (not having experienced such) to be something that would be noticeable in operation.

      Failure for the sear to lock the piston to the rear would, to me, implicate something wrong with the trigger group or the mating edge of the piston. An adjustment that is preventing the sear/trigger from engaging and hence allowing the sear to release the piston as one releases the cocking lever; or a sear/piston engagement surface that has been worn such that the piston can override the contact.

      • The cocking action will not run the full cycle now. The first 4-5 times I
        tried to cock when this happened , it would run closer to whole cycle. But
        then it got so it will only go till barrel is at right angle and stops. I
        had a broken spring in my BSF 55N once that acted like this did at first,
        run most of cycle and not catch trigger assembly. Also had stock off and
        some of spring coils are not uniformly spaced toward to the trigger. Any
        suggestion appreciated.

        • It sounds like a broken spring. If you don’t want to mess with it, just call Umarex, since it is only 5 weeks old. On the other hand, if you don’t mind getting into it, JM probably has several springs that will make you even happier.

    • baldred

      Did you by any chance adjust the trigger? Sometimes trigger adjustments, if done to far, can change the geometry of the sear inside the trigger unit such that it cannot catch the piston.

      A broken spring typically results in an easier cocking stroke, scraping noises and reduced power. I have not heard of broken springs resulting in the piston not catching on the sear, but as Mrs. Slinging Lead often points out, I don’t know everything.

      If the problem is not due to trigger adjustments, I would send it back.

  16. Maybe I’m wrong but ain’t that why Muzzle brakes came about. Not silencers but a weight added to the front of the barrel. The muzzle end if you will.

    The extra weight helped to stabilize the gun.
    Ain’t that what the competition shooters do. Add weights.

    I believe that is what helps the Marauder rifles. It is very easy to make the guns muzzle heavy when you hold them.
    People talk about the factory stocks being wide and heavy. I think they tryed to incorporate every aspect that was possible for accuracy into the factory guns.

    So Mr.Bull was a good shot in the day. But mostly he was smart. He learned what worked.

    Maybe there is people that listen, learn and imply.

    • GF1…

      You might just have come up with a good blog topic for B.B. .
      “What are all of these devices attached to a gun really for ? What is their REAL function?”


      • TT
        I agree. Look at the higher end competition air guns. They have all kind of options for adjustments. Different weights and such.

        Then like you were saying. There is muzzle brakes, air strippers, silencers and so on.

        And just imagine a blog about add on accessories for air guns.

  17. Target barrels generally seem like bull barrels. Are they higher quality? Does other materials like stainless steel etc…..help? I only know a few things about bull barrel, but I guess I never asked too many questions beyond the manufactures literature.

    I always wondered about the plastic bull barrels on airguns.


    • AJ,

      Materials do help. Stainless has not been a good barrel material until recently (the last few decades). Before that it didn’t cut smoothly. Now it is a fine barrel material.

      Yes, usually bull barrels are better-made because of the expense of the material. They don’t waste time on a barrel that costs a lot in raw materials. They put more care into its manufacture.


  18. BB,

    I love all the recent topics. It had been bugging me for years when the first “bull barrel” Gamos came out, that they were standard barrels clad in plastic. They looked so cool – with 1500fps velocity too…
    I thought my IZH 61 was a little barrel light, so I made a heavy barrel sleeve (steel) that looks like a suppressor. I find it even easier to keep steady, and compared to the model I have without – I find it more pleasant to shoot. My 10/22, Savage 93 & Mark II rimfires all have Bull barrels, and I think they all have better handling characteristics than my rifles with standard barrels (personal opinion – I don’t carry them very far). I didn’t think it necessarily applied to spring airguns, since having the propulsion “in” the gun added so much substantial weight. But the muzzles are pretty puny in comparison and depending on the velocity there is some muzzle jump.. I liked the sleeves on the LGV Olympias, and that feature on the R11/HW98 appealed to me as well. I really love the balance of that rifle. Maybe an aftermarket feature for other springers.

  19. Is the bull barrel on the “Benjamin Trail NP Hardwood Break Barrel Air Rifle (.22) powered by Nitro Piston” the real thing? or is it a plastic imitation? Thanks

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