by B.B. Pelletier
My apologies to Jane Hansen. I’d promised her another report on the Blizzard S10 today, but I came down with a horrible stomach flu Sunday morning. My wife, Edith, quickly pulled together this article from the April 2001 issue of the Airgun Letter, as I was in no shape to give the S10 a fair shake.
On to day’s blog.
We say pellets can’t travel much over 900 f.p.s. and still be accurate, but does anyone really know for sure? If 1,200 f.p.s. is too fast for accuracy, why would pellet gun manufacturers tout that speed and greater for their magnum air rifles?
These days, many manufacturers offer at least one air rifle with a top velocity well over 1,000 f.p.s. It’s easy to speculate that they’re just doing it because the public doesn’t know better. But is that really the case? Or, is supersonic velocity not the horrible block to accuracy it’s cracked up to be?
Can an airgun be accurate at 100 yards?
I plan to shoot an airgun at 100 yards for the long-range accuracy test. That seems to me to be the equivalent of shooting a 45/70 at 500 yards or a 30/338 at 1,000. When I shoot that far, I want all the velocity possible consistent with accuracy. Yet, the diabolo pellet I will shoot is a high-drag projectile that starts putting on the brakes the moment it exits the muzzle.
All projectiles slow down, of course, but the diabolo is designed to do it very well. It’s the antithesis of the Sierra Matchking 168-grain boattail, which is designed to slip through the air with a minimum of resistance. Think of the Sierra as a spear and the diabolo as a badminton birdie.
Why do I want all this speed? Simple–to flatten the trajectory. A diabolo pellet leaving the muzzle at 900 f.p.s. will drop 3-5″ by the time it reaches 50 yards, depending on the pellet used. You compensate for this drop by aligning the sights so the pellet appears to rise for a while before falling again, but that adds another twist to the equation. You can be just as far off-target at 10 yards as you are at 50 if your sights are positioned to give apparent rise for the first 30 yards of flight! How much better it would be if you could just sight-in at 50 yards and know the pellet would always be within an inch of the line of sight from the muzzle out to 70 yards.
Higher velocity will help flatten the trajectory, even though the diabolo shape of the pellet still slows it down rapidly. So, why don’t more airgunners shoot at speeds above 1,000 f.p.s.? Because of the sound barrier.
Chuck Yeager wasn’t the first to break the sound barrier
When I was a boy in the 1950s, the sound barrier was on everyone’s lips–especially little boys! Chuck Yeager had officially broken through it in level flight for the first time in 1947, paving the way for a new age of high-speed flight. By the time I became aware of things, people were already talking about Mach 2 and Mach 3, as new records were being set all the time.
What is the sound barrier? Webster’s Encyclopedic Unabridged Dictionary defines it as “a sudden large increase in aerodynamic drag that occurs as the speed of an aircraft approaches the speed of sound.” Of course, the object doesn’t have to be an airplane for the effect to occur. It happens to all objects, including pellets.
I remember the early movies about breaking the sound barrier. They emphasized the extreme buffeting an airplane suffered as it approached the speed of sound. Indeed, many early attempts on the sound barrier ended when the airplane actually broke from the stress. But mankind had already been exceeding the sound barrier for more than two centuries by the time Yeager made his historic flight. They had done it with bullets.
If you’re a shooter, you should be interested in aerodynamics
By the time gunpowder had advanced to the stage where it was reliable and relatively clean burning, musket balls were breaking the sound barrier. They were also getting buffeted, just as Captain Yeager would in his Bell X-1, only there was no way anyone could sense it. By the 1730s, men like Daniel Boone knew that a rifle that cracked was shooting better than one that sounded off with a hollow boom. They didn’t know what made the crack, just that it was the right way for a rifle to sound. They shot round lead balls in their rifles–balls that also slowed down rapidly, though not as fast as diabolo pellets do. But because their rifle balls were made of solid lead, the aerodynamic buffeting did very little to alter their path to the target.
Later, men learned to spin projectiles faster with a tighter twist rate, allowing the use of longer bullets. These bullets were even less affected by the buffeting because they weighed two to five times as much as the round balls. Because they were so heavy, they were not as affected by drag as the smaller balls, hence they retained more of their initial velocity for a longer period, which also meant they went farther at supersonic speeds. That was what was needed to extend rifle accuracy from 100 yards to 1,000 yards and even beyond. By the 1870s, long-range rifle marksmanship was as popular as professional football is today.
During this surge of rifle marksmanship, but in no way connected to it, the small-caliber airgun was born. In 1842, the Oscar Will company made a dart-shooting airgun. By 1876, Quackenbush started cranking out relatively inexpensive pellet-shooting guns by the hundreds. In 1886, the Markham company came out with the very first BB gun, which was soon followed by the first model from Daisy. And the rest, as they say, is history.
Airguns proliferated in greater numbers than ever before as their prices dropped steadily. By the 1920s, larger-caliber airguns, the ones we now call “big bores,” were but a memory and the ubiquitous BB gun was dominating the market–at least in the U.S. Elsewhere, precision air rifles and pistols began to rise from the ashes of World Wars I and II. They were beautifully made and shot as well as the technology of the time permitted, but they were all relatively low-powered by the standards of today.
It wasn’t until 1982, with the introduction of the Beeman R1 Supermagnum air rifle, that a production airgun intentionally shot faster than 1,000 f.p.s. That marked the first time the high-drag diabolo pellet was pushed anywhere near the aerodynamically challenging sound barrier. In four centuries of airguns, there have been less than 20 years during which pellets have been pushed past (maybe) their design limits.
The Beeman R1 was the first production air rifle that could reliably exceed 1,000 f.p.s. It started a trend toward higher velocities that took diabolo pellets where they had never gone before.
The R1 was soon upstaged by the even faster Laser option for the same rifle. That was followed by the expensive Venom Mach I rifle (interesting name, no?) and then a bit later by the much more affordable RWS model 48/52–an air rifle that has no problem pushing .177 pellets out the spout at 1,100 f.p.s. After about 1986, the number of guns that could exceed the sound barrier grew steadily with each passing year.
But the diabolo pellet hasn’t changed much since it was first invented almost a century ago. Its high-drag, forward-weighted shape was purposely created to keep the nose of the pellet pointed along the flight path when shot from a smoothbore airgun. Like a dart or arrow, the drag on the tail automatically orients the pellet in flight, making spin unnecessary–a good thing when you’re shooting an airgun like a Gem smoothbore. But not so good when you want to shoot past the sonic barrier.
The diabolo pellet is shaped like a child’s top. The narrow waist, flared skirt and hollow base all increase the amount of drag on the projectile. That, plus the forward-biased weight distribution, keeps the pellet stabilized in flight–with or without a spin.
I often try to find parallels to airguns in other shooting sports. Where the question of accuracy versus velocity is concerned, I don’t have to look any farther than the good old .22 rimfire. As everyone knows, slower is more accurate with the .22 long rifle. Unless all the competitors, ammunition manufacturers and gun makers are wrong, the most accurate .22 rimfire shoots a bullet at something well under the sound barrier. Eley Tenex, Federal Gold, Lapua Match and the other top names in match-grade rimfire ammo all stay well under 1,100 f.p.s. These are the cartridges folks are shelling out $10 and more for just 50. You and I try to buy a “brick” of 10 times that amount for the same price, but we don’t compete with the same crowd, do we? [Obviously, ammo prices have changed a lot in the 8 years since this article was written!] We like to bounce tin cans around, while they’re competing for gold medals on the world stage.
The weight of the majority is going with subsonic rimfire ammunition where top accuracy is concerned, and they’re voting with their deep pockets. These shooters typically buy 10,000 rounds at a pop at those high prices. When was the last time you bought 10,000 pellets, for a fraction of the cost, and didn’t flinch?
Remember, too, rimfires shoot heavy lead bullets–not thin hollow cylinders. Though some of those bullets have cupped bases and “heels,” they don’t have nearly the drag of our diabolos.
Stay tuned for part 2 later this week.
36 thoughts on “Velocity vs. accuracy: Does it REALLY matter? Part 1”
BB – get well soon!!!!!!
We were down 2 guys at work and our back up driver was on vacation, so I worked two 14 hour days last friday and saturday. I also took ever pill in the medicine cabinet. I was hit hard and fast, but it left the same way.
This blog stated:
But the diabolo pellet hasn't changed much since it was first invented almost a century ago. Its high-drag, forward-weighted shape was purposely created to keep the nose of the pellet pointed along the flight path when shot from a smoothbore airgun. Like a dart or arrow, the drag on the tail automatically orients the pellet in flight, making spin unnecessary–a good thing when you're shooting an airgun like a Gem smoothbore. But not so good when you want to shoot past the sonic barrier.
The diabolo pellet is shaped like a child's top. The narrow waist, flared skirt and hollow base all increase the amount of drag on the projectile. That, plus the forward-biased weight distribution, keeps the pellet stabilized in flight–with or without a spin.
Now wait a minute…
So all of this time I've been thinking I needed to only concern myself with rifled barrels for accuracy (shooting subsonic powered guns)?
So a gun like the Gamo Viper Express (shotshell and pellet gun) could be just as accurate out to the same distance shooting diabolo pellets, as a similar powered airgun with a rifled barrel? The rifled barrel is moot?
Thanks, that's my question also. It's been running around in the back of my brain for quite awhile. I am eagerly awaiting the answer to your question.
However, I'm leaving for vacation on lovely Cayuga Lake, not too far from the Crosman factory, for a couple of weeks. Gave then a call and found out that they really don't do tours for individual folks. I'm looking fwd to thinning the red squirel population around the cabin. I'll be thinking of Troy on his roof.
B.B., Hope all is now well with your innards.
Don't read things into this. No, the diabolo pellet, which is practically ALL pellets, will not be as accurate in a smoothbore gun as in a rifle. But it will be more accurate than a round ball will be in the same smoothbore, unless the round ball happens to fit the bore exactly. The high drag of the diabolo pellet does help the accuracy.
That's why shotgun slugs are accurate without a rifled bore. Drag does for pellets what it does for darts. It keeps them flying straight.
And the range does make a big difference. The Viper Express is more accurate at close range than it should be because of diabolo pellets. But it is not as accurate as a rifle. And at long ranges it isn't close.
Combine rifling with a diabolo and you get a winning combination for short-range accuracy. Today we are pushing the limits of this short range, but we will never be able to challenge bullets.
This article has me thinking about the 17 HMR round. It pushes a 17 grain .178 bullet at 1900 fps. On a windless day my Marlin 917VS can make dime sized groups at 100 yards, and about 1 inch groups at 200. The groups open up greatly at 300 yards, and its due to the bullet going subsonic at that range.
BB, I hope you're feeling better.
So why don't we see bullet style ammo in .177 or .22 for pellet guns? Couldn't one be made with thin rings on the outside so it could still be loaded/swaged by hand? This might present a loading problem for clip fed guns but a break barrel will take anything you can cram into the breach.
OMG, it's better than sex!!!
The Crosman Nightstalker!
It arrived Friday afternoon. Took it down to the basement, gave the instructions a quick read, loaded up a cylinder and some RWS Superdomes to sight it in.
30', using a 10 pistol target. First shot was in the 10 ring. All 11 following shots (it's a 12 shot repeater) literally blew out the 9 and t10 ring.
Saturday off to our shooting spot with the Nightstalker and the boys and their Red Ryders, plus a load of firewood, cheese smokies….
I could put out a pop can at 50' and hit it repeatedly with ease. In fact the pellets struck with such authority that the can would fly out a couple of feet further every time it was hit.
One can started at 50' (I'm anal about measuring these things), and 12 shots and 5 seconds later it was sitting at 78 feet, all but one shot a hit.
The only downside!?
An hour went by in no time and with it an 88gram cartridge ($12) and a $10 tin of pellets.
I'll decide this week what kind of sight I want to put on it, but in reality it will be only to make it look more Tactical…the Mohawk sights supplied with the rifle are in my opinion one of the best set of stock open sights I've ever seen.
There have been bullet-style "pellets" and all have been unsuccessful to some extent. Most were too hard to load, but all require velocity that only a few powerful PCPs can deliver.
Also, solid bullets change the nature of a pellet rifle into that of a firearm. A Condor that shoots a 28-grain bullet at 1000 f.p.s. becomes a .22 short.
wtg cbs dad!!!!
I ran through a box of 25 12g CO2 bulbs and several tins of old and unworthy pellets through my 1077 when I first got it. Co2 airguns can eat pellets fast, but if you watch your deals it can still be as affordable as .22lr ammo or approx. 2 cents a shot.
bb – a condor is close enough to a is a .22 short in my book with pellets.
Oh man, watch out! BBs probably down sizing Sierra MatchKing bullets for his 100 yard test. Airguns seem to work well for me at 75 yards, my range doesn't go to 100. At 75 yards, my Storm XT out shoots my RWS34 and shoots 3inch groups with Crosman Premier Heavys. Of coarse with no wind and a bi pod.
Good luck, try arcing some lower velocity guns (900fps) in your test, mine seem to do well.
Shadow express dude
Pay attention to your health!.. please don't push yourself back to work!
Traveling really puts a hit on your immune system..
Now that's a great article for us now… and it's a great one to run every few months..
Folks really can get caught up in the high power air rifles.. and then find they can't hit what they want.. but.. that said..
I am impressed with the accuracy of the Evanix Blizzard.. Mine is blasting the 18gr. JSB at 1,050fps.. and I would have thought accuracy would be suffering.. but the other day, she gave me a 10 shot mag in 1" at 50 yards, from the bench rest… and it looks like the there is no "tumbling" of the pellets.
Could it be Evanix has found the secret? The AR6 can't touch the Blizzard for accuracy, smoothness, or for quiet shooting… they have really made gains!
Ashland Air Rifle Range
You know, BB, the Gamo Hunter Extreme is has been out in .22 cal for a while now. I'm looking forward to a review on it.
And I probably promised to do it (the Gamo Extreme in .22). The trouble is, there isn't enough time. Do you see how late I am with all the other guns I'm testing?
The best and fastest thing for you to do is to interpolate the test I did on the .177.
Where are you shooting?
If I ever go there, I will remember not to eat the food or drink the water.
Got the "Thai Revenge" first time over there (1972) and don't want anything like it again.
After a few days there is not one brand of toilet paper that is soft enough.
For BB and all the die hard airgunners out there:
I have no doubt you'll get better with the pharmacopia that Edith has at her disposal.
I have the answer to the reason why companies push pellet velocity! It comes from the land of radio control. I was recently debating whether to buy a 1:10 scale "truggy" (about a foot long) that is advertised to go 70+mph. I called up the company to ask if you could turn the car at that speed or anything close to it, and the answer was: "You'll be cartwheeling man." In other words, this speed has no functional purpose at all. It is a scale speed of over 700 mph which means its only value is for people who like to drive it in a straight line in a parking lot while aiming a radar gun at it. So, I still think the hyper-velocity pellets are pure marketing.
My excuse for the r/c interjection is that it's all B.B.'s fault. You can't believe the influence of even a single blog!
Back from a trip to Hawaii. Regarding the question of whether it makes any difference shooting in scenic surroundings, I would say no. Within the Carlos Hathcock bubble of concentration, all places should be the same.
I made some progress with the 1911. At first with sights elevated to maximum, I was grouping perceptibly at 25 yards about 2 feet below POA. It was clear that I was mentally if not physically closing my eyes at discharge and heeling the gun in response to recoil. Using my airgun training, I LASERED in my vision on the POA to force follow through and raised the group to within a couple inches of POA. I also noticed that without heeling the gun, the raging beast in my hand started to feel very light and easy. I begin to see it.
I also managed to truly interface the M1 with my airgun technique, so that banging it off felt like the B30. Magnificent gun. Wayne, without an M1 and a 1911 in .45 ACP, your shooting experience will be incomplete.
I can tell by your remarks that you have arrived with both guns. The 1911 is really a pussycat, once you get to know and understand it. And the Garand is the only centerfire rifle from which is cannot detect a kick. I know it's there, but the duration is so long that I can't feel it as a kick.
On the other hand, if you want to feel some recoil, shoot a '98 8mm Mauser or a Taurus Raging Bull in .454 Casull. They both kick hard.
CSD, glad you like your new gun. I was planning on bringing mine out for a shooting this weekend, but then it rained. Shame.
Sorry to hear you're not feelin well.
Maybe it was to many marshmallows
around the bonfire with Paul and crew:)
Good show on pneumatics but you convinced
me I don't want the 392 for plinkin.
the way you strained when pumpin was funny
On 8/5/09 @ 6:24 AM I asked a question about a CO2 2250 that I was having trouble getting a CO2 Cart. to load in. I just received the parts I needed from Corsman so I decided to tear it apart. What I found was an aftermarket valve that had a fixed, flow through piercing port (for lack of a better description). I believe the gun was set up as a bulk fill gun at one point, even though the guy I bought it from denied it. There is a hole drilled in the tube where a dummy cart. would go. I'm not sure if the valve was actually designed to pierce a cart. or not, but it will if you crank it down hard enough. I put the stock valve back in and everything works fine.
Great information in this post, and coincidentally a question that I've been thinking about lately. Based on B.B.'s consistent statement that velocities near or above the speed of sound, I've been looking towards heavier pellets to keep my fps under 900. I'm curious as to exactly how much air resistance increases at close to the speed of sound. How much does resistance drop once the speed of sound has been exceeded? How does airflow around the pellet change at supersonic speeds? What happens as the pellet decelerates to just below the speed of sound – does resistance increase again?
Also, B.B., I'm not sure you saw my earlier question asking if you wrote an airgun section for The American Rifleman – I remember poring over them as a kid. Back in those days, before the Interwebs, information on airguns was very difficult to find, so one can imagine my glee at finding a whole stack of AR magazines at a local range.
Carlo, I don't know about bullets, but for planes, the biggest mechanical challenge for airplanes is the transonic (Mach .8 to 1.2) area of flight. Past that, the biggest issue is thermal stress.
The physics work for bullets, too.
I write for Shotgun News. I would like to write for American Rifleman but they haven't asked and with the weekly television show I do, I am as busy as I can be.
This promises to be very interesting indeed..(of course, further review of the Blizzard will be interesting as well).
Transonic ballistics is very complex, and we pellet-gun shooters are getting right into the worst part of it..
22-cal rimfire competitors shoot at short range and relatively fixed distances, so thay can avoid the issue with match-grade ammo that can deliver high-consistency and stay below the speed of sound.
High-power hunters, (the old "30-06" guys), are so far above the sound barrier that their projectiles hit the target without ever falling below it, thus avoiding crossing into the "danger zone". The projectile that can travel well supersonic is different than the one that can slow through the barrier..
We who seek distance variability are faced with that awful temptation of trying to ride-out that transition of slowing down through the sound barrier.
As air rifles become more powerful, the temptation is simply irrestistable….
H & N makes pellets in both .177 and .22 called Rabbit Magnum II. These pellets are of the conical bullet shape that BB speaks of and in .22 caliber they weigh 24.7 grains. While there is plenty of heavier ammo out there I think these should be very nice in a 30+ft lb rifle if a target presents itself that is larger than their namesake. Maybe PA will carry them?
From now on, I'm typing up long posts in Word, and pasting them here. Another one that got lost in the tubes:
Well, an interesting situation has developed.
I brought my Nightstalker out this evening, because the sun was setting and I wasn’t up for setting up the 2260, and I made a very interesting discovery. A .177 Crosman Premier Light going 500 is powerful enough to knock over the Gamo steel squirrel, something I had not expected. So I now have two CO2 guns in two different calibers, shooting from two different power sources.
I now have three choices:
A) I could sell one of them, but I am reluctant to do so as the 2260 is brand new, and I have an emotional attachment to the Nightstalker, which was/is my first gun.
B) I could convert the 2260 to .177 ammo, which would eliminate some of the incompatibility. I need to buy a left-hand breach anyways, so a .177 barrel would be complete the swap.
C) I could always leave both as is, but my wallet doesn’t really like that idea.
I calculated out the cost per shot, and the Nightstalker costs six cents to the 2260’s five, but the Nightstalker can also go through ten times as many rounds in an hour.
I don’t want to burden you all with making a decision for me, I was just wondering what your suggestions were as to solving this little “problem.”
Hope you're feeling better. Glad to hear the confirmation about my guns. I felt like I had broken through to a new level, but I have felt all sorts of mistaken things. I'll be very interested in the 1911 technique tape when you have a chance and so will many others, but obviously there's no rush.
Jane, how interesting about the sound barrier. I thought that problems applied to everything at the sound barrier and faster, but it sounds like turbulence is restricted just to the transonic region. Faster and slower is okay. I don't find the variable-distance ideal to be that alluring myself. I believe Wayne makes the best case for it with the S410 that can be shot indoors and out. However, it seems like you'll get better performance by bracketing the transonic region with an air rifle and a .22 LR. Even the S410 will struggle to reach out to 100 yards. In the words of Secretary of Defense Robert Gates, it is a narrow solution to a niche problem. And it seems that even if the capacity for greater speed appears, you will still suffer degradation of performance as a gun tries to operate across a greater range of distances.
Jake, applying my IZH 61 experience, I would say stick with the sentimental value and the high capacity. You can limit the shots of high capacity but you cannot increase the shots of low capacity. And most of all, go with the accurate rifle. Do you find the Nightstalker as accurate as B.B. did?
Matt, I don't know. I've only shot it on the irons, and never at a paper target. I have an old 4x airsoft sight that I could mount on it, and then give it a spin. I just would feel embarassed dumping the 2260 so soon after I bought it. Plus, it has a lot of potential.
What did you decide to do regarding your IZH-61 situation?
Re: "Even the S410 will struggle to reach out to 100 yards."
Wayne's shooting a .177 S410 so I can't speak to that caliber. I've been shooting my S410 in .22 caliber more than all my other airguns combined recently.
I'm at that juvenile stage in airgunning where long distance shooting has consumed me. I have a target set at 118 yards. This past weekend the wind was 5-10 mph which is calm where I normally shoot. My best 5 shot group group, with jsb 18 gr, was 1.32 inches. No question the gun can do better, not sure I can.
The AA S410 may not be the most accurate long range gun but I'm not looking for another pcp because I'm convinced I can shrink these groups. Once I wring out every ounce of accuracy that I think this gun is capable of it's gonna be hard to convince me that there's a more accurate pcp in .22 caliber.
The best group this past weekend were jsb 18 gr. Less wind and the jsb 15.8 (red tin) do very well. Many S410 owners rave about the kodiaks but they are just so so in my gun at long range. Up to 30 yards there isn't a pellet I've tried that isn't accurate in this gun.
I bought my Magnum 350 new. When shooting without scope, the gun had an intrinsic tendency to shoot all its shots to the right side of the target. There was no problem with elevation as all shots were in the same horizontal line with the target center. So, I tried to adjust the widage and it actually worked but not to the desired extent; i.e. I set the windage to the right-most limit it could reach on the rear sight but the shots were still significantly inclined to the right of the target center ,though better than before. Apparently there is no bent (eigther vertical or horizontal)on the barrel as I got it new. Will you please tell me where the problem might arise from? and is such problem common in air rifles? All in All what should I do?
Thank you very much!
If your gun is shooting to the right with iron sights you must adjust the rear sight in the direction that you want the pellet to hit, LEFT in your case. Please read this great article that B.B. wrote (I found this using the search box on the right side of this page):
You may also want to check your stock screws, trigger guard screws and barrel pivot bolt for tightness.
I read the article.It was great as you said. Thanks for your guidance.
Please keep us posted on the progress. Most airgunners, like you, are asking and answering each others questions and sharing airgun related stories in the "comments" section under the most recent article that B.B. has written (B.B. writes a new article everyday Monday-Friday).
Here's a link that will take you to B.B.'s most recent article everytime:
Look forward to hearing the progress or problems with your 350!
How about a shooting comparison of the Blizzard, The FX Cyclone or Royale 400 and the Daystate Air Ranger. All repeaters and all supposed to be very accurate with a lot of power. The FX models a bit less but good anyhow. Try the Daystate in the 50 ft lb version to keep the comparison as equal as possible.
Will help me in deciding which way the money goes on my next purchase…