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Ammo Pellet calibers — why .177?: Part 1

Pellet calibers — why .177?: Part 1

by Tom Gaylord
Writing as B.B. Pelletier

diabolo pellet
The diabolo pellet exists in four smallbore calibers.

This report covers:

  • Smallbore calibers
  • Before diabolo pellets
  • Birth of the diabolo
  • Ideal for plinking
  • Highest velocity
  • Velocity wars
  • Target shooting
  • Field target
  • Summary

Sunday while I was walking through the hall in my church a man stopped me and said, “You know a lot about airsoft? You’re the grandfather of airsoft?” He had been talking to our youth pastor who works part-time at AirForce Airguns and he was trying to remember what he’d just heard.

Most readers can guess my response, but once we were on the subject of airGUNS, he said he needed a good air rifle — something to use on pests. He told me that he was aware such guns cost as much as $100 or even $125, and what would I recommend?

What I would recommend is an education, but of course I didn’t say that. We have all been where he is now and we had to learn from someone! That started me thinking about the basics. A couple weeks ago I completed the series on How to mount a scope. There were plenty of basics in that series, but we also went into some of the more advanced principals. I thought that would be a good approach to use for pellets, as well. Let’s see where this goes!

Smallbore calibers

There are four smallbore airgun (pellet gun) calibers — .177, .20, .22 and .25. I’m going to leave BBs out of this discussion because they deserve a series of their own — and they will get one. In this series I will look at each smallbore caliber on its own. Today I’ll begin with the .177.

Before diabolo pellets

The .177 dates back to the early 1900s, along with .22 and .25 calibers. Before that there were slugs that could be called pellets, though they weren’t in the same class as the diabolo we know today. There was the cat slug, the burred slug (which is the same as the cat slug but by a different name) and the felted slug. All were solid lead with some kind of tail that increased drag.

Cat slug

felted slug

Birth of the diabolo

Sometime around 1905, the diabolo pellet was born. There aren’t solid histories of this anywhere that I know of, but from pellet boxes we know that the diabolo existed before 1909. And there were British trials conducted with diabolos in 1908, according th Walter. I say 1905 because that’s when the H The Lincoln rifle that was to become the BSA rifle was born.

The .177 was right there with the earliest true diabolo pellets. At the time it wasn’t the favored caliber because of the small size of the pellet. It was found most often in ladies model airguns. But that didn’t last. Even back then it was obvious that if all you wanted to do was shoot or plink, a less expensive pellet was best, and even back then the .177 was cheapest because it used less lead. 

Before we leave this topic of diabolos I want you to understand that at the time it was not clear they would be the pellet design of choice. Several other designs were tried at the same time. Diabolos just outlasted all the others. Even today some solid pellets are attempting to break back into the market. But the diabolo reigns supreme.

Ideal for plinking

This is the first big advantage of the .177. They are the ideal plinking pellet because they use less lead. Less lead means a cheaper pellet. To offset the difference in cost the larger calibers are now putting fewer pellets in a tin. A typical .177 tin still holds 500 pellets, where a typical .25 caliber pellet tin holds — well there really isn’t a “typical” 25-caliber pellet tin. They hold from 83 on the lower end to 350 on the upper end.

If all you want to do is shoot at things and watch them move or make noise when they are hit, the .177 is the best way to go. Oh, the heavier pellets will make more noise and move things around more, but the .177 gets the job done.

Build a Custom Airgun

Highest velocity = best-selling

Velocity is a strong selling point for airguns in the lower price category, and that is the category that sells the largest number of pieces. The profit margin per piece is usually the lowest, but the volume that is moved more than makes up for it.

What that means is the most “popular” (best-selling) airguns are going to be .177 caliber. More airguns sold translates to more pellet sales in that caliber, with the result that the .177 caliber pellet is the best-selling of all four smallbore calibers.

Velocity wars

The high-velocity wars began in the 1970s — about the time that personal chronographs became affordable. Prior to the 1960s if you wanted to know how fast a pellet went you had to enlist the services of a commercial laboratory. W.H.B. Smith who published Smith’s Standard Encyclopedia of Gas, Air and Spring guns of the World in 1957, used the services of the H.P. White  chronograph — a device that occupied several rooms and used the services of multiple people. Its accuracy was one-tenth or less of what you can get from a hundred-dollar chronograph today.

Prior to that time Americans used pellet guns for pesting, while the rest of the world focused more on plinking and target shooting. In a few places, airguns were used for subsistence hunting and they favored whatever they could get that would do the job. The thousands of Crosman 101 pellet rifles that were bought by the U.S. Government in World War II, along with a million rounds of ammunition, were mostly given as gifts to influence tribal chefs in southeast Asia.

So Americans favored the .22, while most of the world liked the .177. The British also had the .25 caliber (6.35 mm) pellet at this same time but no powerplant was up to the task of launching it very fast. So it lagged behind the .177 and even the .22.

Target shooting

Ten-meter target shooting with airguns is an outgrowth of shooting 4mm zimmerstutzens that shot (and still compete today) at 15 meters. Like plinking, the size of the pellet makes little difference to accuracy when you shoot at paper, so the less expensive .177-caliber naturally dominated this category. However, the British, notable contrarians that they are, did make several target rifles in .22 caliber, and even Diana and BSF of Germany did the same. But all of this was before the world cup and finally the Olympics put their stamp of approval on .177. When they did that all the scoring gauges were standardized in .177 caliber (4.5 mm). Today the .177 caliber pellet is mandatory for national, international and world competition.

Field target

The far less popular sport of field target (millions compete worldwide in 10-meter target shooting, thousands in field target) also favors the .177 caliber, though it is not mandated. The reason it is favored is statistical rather than rule-based. In field target you shoot through a hole in a steel target at a moveable paddle that stands behind. If you hit the paddle and it moves far enough, the target falls and the shooter is awarded a point. But if the pellet strikes the steel target first as it is trying to pass through the hole, it pushes the target backward against the release mechanism. If the push is hard enough, even hitting the paddle with part of the pellet won’t be enough energy to drop the target. The result is no point.

Statistically, the .177-caliber pellet is smaller than all other calibers, giving it a better chance of passing through the hole without contacting the side. Or, if it does touch the side, the .177 is small enough that it has less chance of locking the target in the upright position. It’s a probability thing and competitors understand that the smaller pellet is the best choice.

In recent years the British field target power level cap of under 12 foot-pounds has been incorporated into the world-class rules and the lighter .177 pellets travel faster at the maximum permissible power than do heavier .20 and .22-caliber pellets. A faster velocity means a flatter trajectory that translates into improved scores for everyone. The bottom line of this discussion is the .177 caliber pellet is better-suited to field-target competition  than any larger caliber.


If I don’t address hunting someone will complain. And you can hunt with a .177 caliber airgun. Doing so means your shot placement has to be perfect, as the tiny .177 projectile cuts a narrow wound channel. I don’t recommend the caliber for hunting solely , unless you allow for its shortcomings. Killing mice in the cellar would be preferable to hunting crows in the barnyard. If you want to hunt crows and .177 is all you have, go for it. Just don’t choose the caliber because the pellets are cheaper.


So .177 is the most popular pellet caliber for all these reasons. Can you think of any more?

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.

89 thoughts on “Pellet calibers — why .177?: Part 1”

  1. B.B.,

    The .177 is also relatively safer as that its lower mass equates to lower energy retention at longer distances compared to a .22 pellet that can reach out with still a lot of energy outside of its accurate envelope.


    PS Section Birth of the diabolo 1st paragraph 3rd sentence: “And there were British trials conducted with Diabolos in 1908, according th (to) Walter (Who is Walter? Walther the manufacturer?). I say 1905 b3ecause (because) that’s when the H. The (delete H. The) Lincoln rifle that was to become the BSA rifle was born.

  2. Dude, I must be ancient.
    When I first got into airguns, guys were calling .25 caliber a “big bore”.

    I now know there have been larger caliber airguns for hundreds of years, but other than the Girandoni, they were not widely known to the general airgun population.


  3. B.B.,

    “Can you think of any more?”

    A direct result of more demanding .177 pelt buyers, think competitors, the only pellets that typically had pellet head size selection was .177 wad cutter, with as many as five diameters in addition to nominal caliber. The occasional .22 caliber wad cutter had perhaps three. Then Field Target caused more round nose pellets to come in as many as two additional head diameters but only on select models and from far fewer manufacturer/labels. .20, .22, and .25 caliber pellets almost never have diameter selection beyond the nominal caliber.
    Interestingly very recently when bullets (airgun slugs) in all the small bore calibers started being mass produced and buyers wanted choice of diameter without resorting to DIY sizing dies. It seems that more and more buyers of pellets and airgun slugs are being educated to bore fit = accuracy! Perhaps we will see more pellet calibers offering head size choice or manufacturers may settle on standard bore sizing…not holding my breath on the latter!

    Errata: On the Cat Slug drawing the Caption on the right side lost part of: th(e bore)


  4. BB,

    I am certain you saw this one coming. 😉

    “OK boys and girls! It is time for your history lesson with Uncle RR!”

    The diabolo pellet started sometime in the late 1800’s and was in use in the very early 1900’s. Whoever came up with the design must have been an avid badminton player.

    During the Boer Wars, the British discovered their soldiers were very lousy shots and the Boers were superb marksmen. To correct this issue, the British government began encouraging their subjects to take up airgunning and even sponsored competitions. There were quite a few gunsmiths around Birmingham at the time who began buying German air rifles and converting them to .177 competition air rifles for the British market.

    One of these gunsmiths was Lincoln Jeffries. He decided to design a competition air rifle from the ground up and patented his design in 1904 and began building them. In 1905 he approached BSA and offered to sell the design to them with the stipulation he could continue to build them also. In late 1905, BSA began producing the Lincoln Jeffries Model BSA air rifle. BSA continued to build this air rifle, with a brief interruption from 1914-1918 and slight design changes, until 1939. Mine was built in March and April of 1906.

    Historical side note: The barrel locking mechanism on this FLZ air rifle was patented in England in 1905.


    This particular air rifle may be older than initially thought.

    What does all of this have to do with diabolo shaped pellets? That is what they used.

    Hey, this is all your fault! You told me to buy that air rifle! You started it!

  5. Thanks B.B.!

    Really enjoy this kind of blog!

    I have taken hundreds of squirrels and rabbits with a .177 airgun (FWB 124) but while it is adequate for pesting, I would not recommend that caliber for hunting. With a .177. a humane kill requires surgical precision – the shooter (absolutely) needs to their maximum effective range (both accuracy and energy wise) and restrict their shots accordingly. Anything but a solid heart/lung or head shot will result in lost game.

    I say this because there is somebody in the neighborhood who is accurate enough to hit a squirrel and wound it but lacks the precision and power to make a clean kill – I have recovered .177 pellets from several squirrels that I needed to put down in the past month.

    Love the .177 caliber for general plinking and shooting but defer to the .22 for small game hunting.


    • Deck,

      Like I said, it is BB’s fault. He talked me into buying that air rifle. Now, all I really want are the “old gals”. The new ones are kind of fun to shoot every once in a while, but I get bored with them pretty quickly. Most of my shooting is with airguns that are far older than I am.

      Now, if I just had a thicker wallet.

    • +1 on the “still jealous” comment . . . . 😉

      I got slammed with work yesterday and did not get a chance to offer my congratulations, so here they are a day late: congratulations!


  6. BB,

    I look forward to the rest of this series and appreciate your focus on the basics. I am hoping that as part of your series on pellets you might address any concerns with long term pellet storage. Is there a way to prevent the white deposits that can form on some old pellets? Is it ok to shoot these pellets that have turned white? Is it some kind of corrosive salt that may damage the barrel? Thank you for any insights you can share.

    If you are feeling generous with your expertise, can you comment whether your prescription for barrel cleaning (only of accuracy suffers- if I understand you correctly) holds true if one is shooting a lot of harder pellets like the Crosman Premiers through a gun that puts them out at 900 fps or above?

    Thanks again!

    • AOB,

      Don’t clean pellets! Cleaning removes whatever anti-oxidant the factory used on them. It’s usuallY A THIN WAX, BUT IN THE OLD DAYS IT WAS OIL.

      If you shoot Premiers you will have to clean the barrel more often. And the faster they go the more frequent ther cleaning.


    • Airman Of The Board
      Get a good Borescope use it to learn what a clean of Leading bore looks like. Then when accuracy (not Precision) drops off see what the bore looks like. The smear of Lead is easily found on what was “rough” spots or edges of the grooves in the bore. Use a Pb (Lead) remover Only with the least aggressive system (Nylon) brush/patch Brass jag that will get the job done.
      More damage is done cleaning bores (firearm and airgun) that really don’t need it than shoot poorly because of other issues…to include fundamentals of shooting.

      My two centavos,


    • AOB,

      The white deposits are simply oxidized lead. It won’t occur if you keep your pellet tins sealed with the tape that comes on them. If I ever want to put an opened tin back in storage, I simply wrap some of that (or electrical tape) back over the tin to keep any air exchange from happening – people forget how much “air exchange” happens through normal cycles of changes in atmospheric pressure causing air to flow in and out of unsealed containers over time.

      In the rare case that I get a tin that “leaked” and I find oxidation, I tend to just plink or tune over the chrony with them.

      Contrary to what BB said, I do like to wash and then re-lube my pellets (usually with either Krytech chain lube or Hornady One-Shot case lube). I do this because much of my shooting is indoors in my basement, and it is amazing the amount of small lead particles that come off the pellets when washed, I and I feel this reduces the amount of “lead dust” and such that comes out of the muzzle.

  7. BB, the flat trajectory is a plus for .177. A gyroscope spins about its axis, but a pellet has almost no axis to spin about. If a pellet had a stem along its center axis, would it spin better or are some shapes better spinners than others? I assume aerodynamics is a separate issue.

  8. B.B.,
    $125 for pests. If someone told me that, my first question would be, what are you calling pests (rabbits, flies, gophers, Wood Bees)? Certainly there are guns at that price range to get the job done, depending on the “pest”. A Crosman 1077 might work or if more power was needed, a Crosman 2100B pump would work. Tough question without more details. Love this report on the different cals. Looking forward to the rest!


    • Doc
      A little more money but a Disco or Maximus in .177 or .22 caliber would be my choice.

      I know a pcp. A pump. But it is what it is.

      But I guess a nice hw50 would add up to a Maximus and hand pump. Anyways a few options anyway.

      Either way. Springer or pcp when it’s all said and done you will need to spend some money to get something that works for you.

      • GF1,

        I have a pair of Weihrauch PCPs (HW 100 in .177 & .22) that I am extremely fond of. Been thinking about getting a .177 HW 30 or 50 break barrel for casual plinking for some time now – which would you recommend and why?

        Thanks in advance for your input!


        • Hank
          Both the 30 and 50 are nice. The 50 has a little more power and cocks a little harder.

          But let me see. How about I say this.

          I have had 3 hw30’s and one hw50. I would go with a 30 over the 50. But that’s me.

          • Thanks GF1!

            Been pondering this for a couple of years now.

            I’m looking for a simple plinker – iron sights, easy cocking, modest power, accurate, with a good trigger. You know, something light weight to smack spinners (and chipmunks ) at 5 to 20 yards.

            In thinking about it, I am just realizing that I want to retire my Slavia 618 and replace it with a quality adult-sized springer. The HW 30 sounds ideal.


            • Hank,

              I have an HW-30S and love it – it is an extremely accurate gun. I love plinking with it and I also target shoot at 10M with it – it is a joy to shoot, and was great from the factory but even better after dropping in a Vortek kit. I have a peep sight on it and love it, and also a quick realease scope mount set up that I can easily add on. It also handles its share of pesting around the house for the chipmonks that try to live near the foundation. I do not have the 50, and thus can’t compare them.

              Since you specifically mentioned an “adult-sized” springer, I will point out that the 30 is actually on the small side. I would not call it a youth gun, but it is something to consider, if it matters to you. I do love mine, and will never part with it. It cocks so lightly and smooth that I think that anyone could shoot it with ease.


              • Alan,

                Thanks for chiming in!

                I like full sized rifles of a decent weight for stability (I find my Maximus to be too light and am making a wood stock for it ) and general shooting at range. That being said, I don’t mind a smaller rifle for quick, close in shooting. The Salvia I have had since my early teens is definitely a small youth rifle – it is small enough to be shot one-handed!

                Thanks for the heads-up, I’ll check the specs on the HW 30 but I think it will be fine for what I am looking for.


              • Alan,
                Thanks for commenting. I have never shot but hear nothing but praise for the HW30 & the HW50. I would like a break barrel that isn’t hold sensitive. I hear these guns are not. I am surprised you was able to kill chipmonks with it. I take it the shoots were head shots. I am guessing yours is in .177 cal?


                • Doc,

                  My 30 is not very hold sensitive, in fact I would describe it as having “just the right amount” of hold sensitivity. If I am consistent in how I hold it it will stack pellets out to around 25 yards, but if I am sloppy in my repeatability the groups get noticeably bigger – not bad, and still very accurate, but not stacked. Very different holds will lead to slightly different POI (as will resting the rifle directly on a sandbag).

                  It is a gun that is both a joy to shoot, and if you watch for it, one that lets you know when you can do better. I enjoy shooting it to keep my skills up, as compared to my PCPs. My best PCP is a .22 Daystate Air Ranger that, at times, I think might just hit what I want even if I don’t aim it properly 😉 – a great gun, but honestly not the best for keeping your skills sharp. The HW-30S keeps me shooting better, especially since, as a springer, it still requires better follow through than any PCP.

                  As for pesting, the chippers are not hard to put down, and my 30 is putting out 7.5 FPE with the JSB RS (the best pellet in mine, but it shoots many very well). It has taken many, and even a few red squirrels too, and those are tougher critters (head shots on those ones, chippers will go down with head or body shots).

            • Hank

              I have a pair of R7s that both give me the most fpe and the tightest velocity spreads with Exact RS pellets.
              They snuff starlings and red squirrels pretty well if I am careful of my aim point.

              I polished the under side of the cocking link and smeared on some moly to slick them up. Cock smooth and easy.

    • Edlee,

      I cannot say for sure, but if I am not too mistaken, this is considered the Model H. BB is a few years off on the H. BSA changed the cocking lever and lever latch slightly from the original design and the H was born. They made several design changes over the years, including giving it a two stage trigger.

      Thanks for the picture!

      • Siraniko

        If you google “H the Lincoln airgun”. you will find a whole lot of very good pictures of this model. I liked the tap loading design and the adjustable trigger was very basic and exposed. See for yourself. It is the vintage airgun forum, I think.

  9. I’ll take a chance at being Captain Obvious here, but .177 caliber pellets are also popular because some hugely popular airguns over the last half century, like the Crosman 760 and Daisy 880, have shot BBs and also .177 pellets.

    • lain -UK,

      Yes, I don’t remember that being used in many other places that way for airguns.
      My first experience was with RAF types at RAF Wyton who were into airguns since their flying hours were cut badly. At first i was flabbergasted when they talked about their airguns being 1, 2, or 3 bore! I was much relieved when i found out we were not going to shoot Punt Guns in Punt Boats on the St. Ives!
      Interestingly usage!
      But it is also an error as are most of the things we believe about projectiles, barrel, and bore sizes.
      The ‘2’ in a 2 bore is not as you might expect a unit of length (diameter) but a division of weight. The 2 refers to two parts of 1 pound of lead or more specifically a pound of lead can be cast into two balls of equal size that equate to the barrel diameter of what we know as a 2-bore. The nominal bore is 1.326 inches (33.7 mm), and projectiles generally weigh 8 ounces (227 grams; 3500 grains).


  10. Shootski,

    From yesterday. I will not deny there is more to internal ballistics than what is usually calculated, but how many places should you calculate to? Beyond a certain point, it is a wasted effort. Slide rules worked just fine. That is what they used to go to the moon.

    • RidgeRunner,

      It isn’t in the calculations. I have my K&E slide rule still and occasionally drive my son crazy doing computations on it. I still use a Wiz Wheel (circular rule) when i fly.
      The issue is that the gas rules (i cant bring myself to call them Laws anymore) may only be aproximations that seem to only work at or near STP…4,500 PSI isnt even natural in most places on the Planet Jupiter. Old Sol is a different matter but then look at what we think happens inside. We can’t even get close to reliable containment that the Sun does 99.999999% of the time.


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