The Oehler Model 35 is a tireless and accurate workhorse.
I have had a mad, passionate love affair with adult precision airguns for over a decade. Airguns have a lot going for them. They can be shot where firearms are forbidden. They are often accurate, relatively quiet, and fun. On a cost-per-round-basis, they are extraordinarily thrifty. There is a great deal about airguns to like.
If there is one area in which airguns are deficient, it is that they are not fast. Marketing claims of high velocity to the side, I don’t know of any airgun that routinely shoots faster than 1,000 fps and is also accurate. I once shot a springer air rifle that claimed 1,500 fps velocity. It would, indeed, shoot very nearly that fast, but it was inaccurate. When I slowed down the velocity by using heavy pellets, the air rifle became quite accurate. Unlike centerfire varmint rifles, an air rifle will not launch a supersonic projectile that stays in the supersonic realm all the way to a target hundreds of yards away. Very fast rifles produce flat trajectories; air rifles do not.
Sooner or later, if you want to push the envelope of what is possible in shooting with an air rifle, you will have to deal with the arching trajectory at which airgun pellets normally travel. There are two basic approaches. The first is simply to go out, shoot at various ranges, see where the gun is shooting, and adjust accordingly. The second the scientific approach is to chronograph the air rifle with its favorite pellet, plug the resulting information into a ballistics program, and then compare the ballistics chart it produces with actual shooting results in the field. For example, you can go to http://airguns.net/trajectory.php and compute the trajectory of your pellet under the conditions that you enter. Or check out http://www.arld1.com/, demos #9 and 13 which can help you visualize your trajectory in a couple of different ways.
To get the exact velocity of your pellet(s), you will need a chronograph. For some years I have been using, and can highly recommend, the Oehler Model 35 Proof Chronograph. What makes it a proof chronograph is that there are three sky screens that work together to make sure the velocity measurements are accurate.
When a pellet passes through the front (first) sky screen, it starts the chronograph. As the pellet passes through the rearmost (third) sky screen, the main velocity measurement is calculated based on the time of flight from the first to third screens. Here’s “proof” part: the Oehler also makes a measurement as the pellet passes over the middle (second) sky screen. The chronograph then compares the two readings. If the measurement from the first to third sky screen does not agree within two percent with the measurement from the first to second sky screen (when using the two-foot rail), the displays blinks to indicate this is a suspect reading. This prevents you from accepting and using bogus information to make your shooting decisions.
In addition to the velocity for each shot, the display also will give you, after poking the appropriate buttons, a variety of data such as number of shots, high velocity, low velocity, extreme spread, and average velocity. I record the information in a notebook, but a version of the chronograph with built-in printer is also available for the less frugal.
My experience with the Oehler indicates it is a tireless workhorse, and I can cheerfully give it my heartiest recommendation without reservation. For more information, call Oehler at 1-800-531-5125.
Once you have a chronograph, what can you do with the data that you get from it? For me, there are two key things. First, you can input the pellet velocity, along with its weight, sight-in distance, and so forth, to compute the trajectory of the pellet at various distances. I have used this technique successfully to set up air rifles for field target competition. In addition, I understand that airgun varminters do similar things for setting up their rifles for clobbering pests at long range. As part of measuring the velocity of your air rifle, you can also see how consistent it is from shot to shot.
Second, you can use a chronograph to periodically test your favorite air rifles and air pistols to make sure that they are behaving well. When my favorite custom-tuned spring-piston air rifle suddenly began acting strangely, I chronographed it and found that the velocity had dropped significantly, indicating that it was time for repair.
Understand me well: if you are serious about airgunning, a chronograph is not an absolute necessity. There are certainly many excellent airgunners who do well without them. But a chronograph can be a very powerful and useful tool.
Til next time, aim true and shoot straight.
– Jock Elliott
Mr. Elliott,
From what I have read about the airguns, it is not the airgun that is to blame for being inaccurate after it reaches supersonic velocities. Although a pellet is given some rotation from the barrel’s rifling, it is apparently not enough – that is why pellets have ‘skirts’, which helps stabilize the pellet in flight. However, for some reason, after breaking speed of sound this pellet design begins to wobble/tumble resulting in the decreased accuracy.
From what I understand, if one wanted to make an airgun that would go supersonic, one would have to make a more bullet-like pellet, which do exist, and also give it enough twist so that it would be stabilized in flight. I’m not sure if that is possible, given relatively low pressures (compared to firearms) of airguns.
It’s probably possible, but I would guess that making such powerful airguns would move them into legal territory on par with firearms, which is why no one does it.
I have only recently found your blog and found it an interesting read. I had a question – you’ve come across many air guns, and I was curious – what would you consider to be some of the most powerful break barrel airgun rifles on the market as of today?
I’m asking because even the most powerful break barrel rifles seem to be suited for small to medium small game. If you wanted to hunt deer or some such, you would have to move to PCP/pump. I am curious why that is – is it simply because such velocities/pressures are unachievable with the break barrel design? What is the maximum power a break barrel can offer?
Cheers,
Igor.
Igor,
Thanks for your note. There are airguns — break barrel rifles — that will launch pellets at supersonic speeds, but they don’t have the power to keep the pellets in the supersonic region. Although I am not a ballistics expert, my understanding is that the real problem with airgun pellets occurs when they lose velocity and drop back through the turbulent transonic region to subsonic speeds. If you saw the movie The Right Stuff, you know what happened to Chuck Yaeger as he approached the speed of sound — it got very turbulent, and turbulence throws off accuracy. The big trick with powder-burning high-speed varmint rifles is that they launch bullets at supersonic speed and keep them above the speed of sound all the way to the target. I don’t know of any airgun powerplant that has the power to launch a pellet at supersonic speed and keep it there for a long distance.
As to your question, the most powerful break barrel air rifle I have ever shot is the Gamo Socom Extreme .25 cal, which makes just shy of 27 foot-pounds of energy at the muzzle. In general, as spring-piston air rifles rise in power, they tend to become more difficult to shoot accurately because of the violence of the powerplant — in which considerable weight of the spring and piston are thrashing around inside the gun before the pellet leaves the barrel. In addition, I don’t know of any spring-piston powerplant that can make as much power as a big bore pre-charged pneumatic air rifle. My guess is that even if you could build a break barrel spring-piston rifle capable of humanely killing a deer, it wouldn’t be much fun to shoot.
The chronograph and velocity information that you put up in this article are very commendable, congrats for that. I’d surely wanna own one of those soon. Thanks a lot!
I’ve just begun using an F1 chrony and as well as being an extremely usedful tool, it’s addicting as well. I own only springers, ranging in power from 10FPE to 30FPE, and it’s been loads of fun learning what each of my rifles is actually doing in terms of FPS and energy. Some like my bone stock Walther Talon have been a disappointment and are now slated for some attention, and others like my tuned XS28 from Mike Melick make me want to get out and shoot every pellet I can find to wring the most performance possible from em. I’m still suffering from magnumitis, so now that I have a chrony, it’s a safe bet I’ll be lightening my wallet even more in the near future in the quest for those high numbers with heavy pellets!
Paul,
Thanks for your comments!
I disagree with the break barrel not EVER being able to produce enough power with stability to gain….. let’s say; 44-50 pounds of muzzle energy. A few of us here in MN are working on a new tri-piston setup with dual core chamber. But there is a twist to this; There will be no break barrel or manual pump. this will be a balanced system and here I will leave you in suspense. .30 cal. Higher velocity, better accuracy, and made “specifically” for deer hunting. See ya soon folks and fans.
Brad,
It sounds like an interesting concept, but I’ll believe it when I get to shoot it.