Why do some airguns recoil? – Part 2 Pneumatics and gas guns

by B.B. Pelletier

Part 1

I’ve grouped pneumatics and CO2 guns together, because they both operate with compressed gas. Therefore, the recoil behavior is the same for both.

They DO recoil!
Make no mistake, all pneumatic and CO2 guns recoil. But, they recoil so little that it’s easier to say they have no recoil to speak of. Compared to a recoiling spring gun, that’s true. When a pellet takes off under the pressure of gas behind it, the rifle moves in the opposite direction. The weight of the moving pellet determines the force of the shove imparted to the rifle or pistol. That’s why the recoil is so light. An 8-grain pellet cannot affect a 40,000-grain air rifle very much. When you get into an air pistol you do start to notice the push.

As the projectile weight increases, so does the recoil
How many times have I read an article in a gun magazine describing a vintage big bore air rifle, where the author says there is no recoil and no sound? It’s obvious to me those writers have spent more time behind the Smith-Corona than the Smith & Wesson! Big bore airguns do kick and some of them hick hard enough to hurt! I remember shooting an 8.5-lb. 118 caliber dart gun called the Mag Air 1180, which shot 550-grain mild steel darts. It was for hunting big game, such as mountain lions and elk, and it kicked about as hard as a .30/06, which is to say…a lot!


Mag Air 1180 is a humongous big bore airgun.

But the biggest kicker I ever saw was a CO2 gun called CO2Much. That was a 14.5-lb. monster that shot a 7-oz. lead slug. It generated over 1,000 foot-pounds, and the recoil was at least as bad as a lightweight .375 H&H Magnum, if not a .458 Winchester. It moved the seated shooter’s shoulder backwards a foot or more, even with the gun mounted on a bipod.

Is recoil a problem for gas guns?
Recoil isn’t a problem for sporters and hunting guns. And, if the power is low, it’s very difficult to feel the recoil anyway. In 10-meter target guns, recoil is a problem, and the top makers, e.g. Steyr and Feinwerkbau, have done something about it. Just as some “recoilless” spring guns use a counterweight to offset the momentum of the piston, the top target guns use a very small weight to offset the push that comes when the gun fires. This weight is also powered by air and moves backward to counter the pellet going forward. It works so well that when you fire a gun that has it, the only way you can tell that the gun fired is by the noise. You feel no impulse.

This system is balanced very close and is one of the maintenance items on guns so equipped. Tiny particles of lead will get blown into the channel where the weight moves and eventually gum it up, so these guns have to be cleaned more often than regular PCPs that don’t have the mechanism. For shooters who aren’t world-ranked, it may be more trouble than it’s worth; but it comes standard on guns such as the FWB P700, so you get it whether you want it or not.

Powerful smallbores recoil noticeably
When you fire really powerful PCP rifles, such as the AR6 Hunting Master and the Condor, you’ll notice a kick. It’s about the same as the recoil seen in a heavy .22 rimfire rifle, but the impulse lasts longer. Since nobody shoots field target with these rifles, the push isn’t a problem. They have more than enough accuracy for hunting, but follow-through after the shot is fired is the right way to deal with recoil, no matter where it comes from.

So, all airguns recoil. Until someone invents a rail gun that shoots pellets, I suppose it will stay that way.

20 thoughts on “Why do some airguns recoil? – Part 2 Pneumatics and gas guns

  1. Actually, even rail gun does recoil – recoil force is exerted onto the rails along the length of the rails while projectile is accelerated and the current is flowing through the rail. That is in addition to both rails being pulled in opposite direction due to the current flowing in the presence of magnetic field.

    After all, you can’t fool a momentum conservation law.

    Alexey



  2. I also forgot to mention that the force is also exerted onto the source of magnetic field as well (it interacts with the flowing current the same way current interacts with it), so if both rails and field source are mounted on the same base you’ll have even greater recoil.

    Alexey


  3. Hey, BB!

    A follow up question to my “casting your own .22 pellets from yesterday. $100 is a fair amount to pay for your own mold–but maybe there’s an easier way!
    How about filling a .22 28 grain Eun Jin, with lead solder? Would the pellet be shootable? How much weight would that make it? If it were possible do you think the effort would be worthwhile(i.e. would ‘you’ do it)?

    thanks,

    Jay


  4. Jay,

    I think the pellets would be off-balance from this technique. I cast bullets and you can’t even do a second pour when you have a void in the mold even before you dump the bullet out.

    B.B.




  5. Mil Dot Range Estimation

    I once found a very good article on this at a site that was called something like Americansniper.com. I can’t locate it now, but for those who have been asking running a google search with the keywords: sniper mil dot estimation range seems to throw up quite a few possibilities.


  6. Your articles on recoil reminded me of something.

    We know that the Marksman 2004 is probably the nicest non-CO2 pellet pistol in it’s price range. The awkward loading and cocking aside, it handles well, has a nice trigger, and is a very smooth shooter that is easy to shoot accurately.

    If you go on reviewcentre.com and look up comments on this pistol, you’ll finde more than one owner complaining about – recoil! Yes, that tiny little jump that this pistol does when you shoot it – some complain that it significantly degrades the accuracy…


  7. Any system that places mass into motion will “recoil”. It matters not what the energy source is, nor how efficient it may be – magnetic, nuclear, electrical, chemical, spring, compressed gas, or anything else. If something moves, there will be recoil!

    Efforts can be made to “balance the mass”, some ideas better than others, but there “ain’t no way around it”

    If someone could find a way to violate this “Law of Physics”, a clever engineer would develop a “Perpetual Motion Machine” and our societies’ “source of energy” woes would cease to exist.

    Momentum


  8. Hello B.B.,

    I hope that you receive this message, as I have been having trouble getting onto this forum to post questions and comments. First, I am looking for a good air pistol to use at home for practice in place of going to the range with my cartridge firearms. I am leaning toward either the Tau 7 or possibly toward the Alfa Proj CO2 pistols (I like the CO2 pistols and the sophistication of these particular air guns). I am also looking for a 22 springer to use for plinking and hunting (nothing larger than Crows, most likely) and was wondering if you can offer suggestions on any of these air rifles and pistols. By the way, I see that Pyramid has some .177 Tomahawks left. What is your opinion of those (Pyramid’s link to your review for this rifle is down). Thanks much.

    Curtis


  9. Hi B.B.,

    This question is off topic, but I’ve noticed my Diana 54 is starting to make a loud crack on firing. It didn’t use to do that and I haven’t changed the pellets I’m using. I’m using Crossman Premiers in the bulk box. Can you enlighten me?

    Nuglor


  10. IS ICS AND CLASSIC ARMY THE SAME COMPANY ( I HAVE HEARD PEOPLE SAY THEY ARE THE SAME I JUST WANTED TO VERIFY) IF NOT WHICH IS BETTER I AM LOOKING AT GETTING AN AIM M4-1-AS AEG FOR AIRSOFT AND IT IS BUILT BY ICS


  11. Curtis,

    There are so many air pistols and rifle that I find it extremely difficult to recommends specific guns, however since you are already predisposed to CO2, I like the Alfa Project.

    For a .22 rifle how about the BAM B40?

    Yes, the Webley Tomahawk is a fine rifle, however they don’t have a scope stop, which makes mounting a scope very difficult.

    B.B.


  12. Nuglor,

    Your rifle is doing one of two things. Either it is dieseling (really detonating, because all powerful spring piston guns diesel on every shot) or the pellets are starting to go supersonic.

    Nothing may have changed except for the weather!

    You didn’t mention the caliber, but I assume your 54 is a .177? You may be shooting at 1050, or so, which has been below the sound barrier until now. A temperature change or pressure change changes the speed of sound.

    There are days when my silenced .22 Ruger breaks the sound barrier with subsonic ammo, simply because the speed is so close.

    B.B.


  13. ICS and Classic Army,

    All airsoft manufacturers tend to use each other’s parts in their guns. As far as I know, ICS is a completely different company than Classic Army, though you might find the same parts in their guns.

    B.B.



  14. Nuglor,

    It only diesels for one reason – fuel. Something in the compression cylinder is burning. It could be grease from the mainspring, if you had the gun tuned. Diana doesn’t put much grease on the spring. Or you may have dropped chamber oil through the transfer port. There has to be fuel for a detonation diesel.

    Solution – remove the fuel.

    B.B.


  15. O.K., that’s interesting. The gun is only a few months old, I probably have around 1000 shots through it. I’ve not had the gun tuned nor put oil on it except to clean and protect the outer surfaces. The oil I use is the Beeman MP-5 Metalophilic oil. I guess it’s possible some of that seeped into the chamber. I’ll have to give it an extra good cleaning.



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