How spring-piston rifles behave

by B.B. Pelletier

Okay, Grasshopper, enough Wax on! Wax off! It’s time to use your skills.

If you’ve been following the discussions over the past month about accuracy, you should now have the tools to be a pretty good judge of the potential accuracy of an air rifle and the relative ease with which that accuracy comes — even before taking the first shot. We’ll confine today’s discussion to just spring-piston guns, since they’re the most difficult to shoot.

How a spring-piston airgun works
This is a review for many of you, but we have enough new readers that perhaps it’s good to go over the points of how the spring-piston gun works. What I’m about to say holds true for guns with gas springs as well as guns with coiled steel mainsprings. They all work the same when it comes to their operation.

When the sear releases the piston, the piston starts moving forward rapidly at 50-60 miles per hour or 73-88 f.p.s. Unless there’s something like an anti-recoil mechanism to prevent it, the gun starts moving in the opposite direction. Since the piston weighs but a fraction of the weight of the whole gun, the gun’s movement is very slight.

Within a few hundredths of an inch of the end of its travel, the piston has compressed the air in front of it as high as it will ever go…given the piston diameter and length of the piston stroke. Due to this compression, the temperature of the air has also increased to a very high point. The piston wants to slam into the end of the compression chamber, but the thin cushion of highly compressed air actually slows it down and can even stop it. The pellet in the breech is sealing the air in front of the piston, and it hasn’t started moving yet.

However, at some point — and that point changes with each pellet used, the pellet can no longer remain stationary. There’s too much force pushing on its tail and it begins to move down the bore. The piston can now go all the way forward and rest against the end of the compression chamber, or it may have done so already and rebounded off the air cushion and now needs to go forward again. Each different type of pellet will determine exactly how this relationship of movement plays out, which is why some pellets feel good when you shoot them and other pellets seem to make the gun buzz and vibrate and even make noises that you may never have heard before.

When the piston reaches the end of its travel, it stops suddenly. When that happens, it imparts a hammer blow to the airgun, sending it in the same direction the piston was traveling. This is the second recoil, and it’s much more noticeable. At this point in time, the pellet is probably between three and six inches down the barrel and the entire gun’s moving.

The movement is in several forms. First, there’s high-speed vibration running through all the parts of the gun. You can’t see this vibration, even on a high-speed camera, but you can feel it. This is the buzz that you feel from some guns, and it can be so sharp that it actually hurts to hold the stock against your cheek.

Next, there’s a lower-speed vibration that’s both larger and much slower. If you had a high-speed camera, you could actually see the various parts of the rifle moving. The pellet is still inside the barrel when this happens.

Finally, there’s the recoil in both directions. Both are visible on a high-speed camera; and the forward movement, assuming we’re talking about a conventional spring-piston setup, is by far the largest. The gun starts moving forward before the pellet leaves the muzzle, but completes the movement after the pellet has gone.

Which spring-piston guns will be accurate?
Simply stated, breakbarrel spring guns are the most difficult to control. They may be just as accurate as underlevers and sidelevers, but they’re almost always more sensitive to the movement of the gun when it fires. That’s not to say that sidelevers and underlevers are not sensitive; but in comparison to breakbarrels, they’re less sensitive.

Let’s stay with breakbarrels for now. The ones with the longest piston stroke have the longest period of time for movement. That includes the high-speed vibration, the low-speed vibration and the recoil in both directions. As a rule, long-stroke spring-piston guns are the most sensitive to hold, and long-stroke breakbarrels are the most sensitive of all.

Then there’s the weight of the piston to consider. A heavy piston causes more rearward recoil when it begins moving and more forward recoil when it comes to a stop. You tend to find heavier pistons in guns with more power.

Put this all together, and you know that a breakbarrel spring-piston rifle that has a long piston stroke and high power will probably be the most sensitive airgun, as far as hold goes. It may be potentially very accurate; yet also be so sensitive that unless the hold technique is perfect, it’ll spray pellets everywhere.

Listen to this!
When I was doing the testing that lead to my R1 book, I tested my .22-caliber Beeman R1 with the factory tune and then with four different custom tunes. One of the tunes — from Venom — increased the power of the 18 foot-pound rifle to 23 foot-pounds, but it also removed nearly all vibration. It was by far the smoothest tune for that rifle. As a result, the rifle became easier to hold and shoot.

I then destroyed all of the mainsprings used in the testing by leaving the rifle cocked for a month with each of them, so the Venomac Mag-80 LazaGlide tune went away. While I had it and used it, I learned that it’s the vibration and not the power of a gun that determines how difficult it is to hold.

That tells us that if the gun is powerful without vibrating, it can be easier to shoot. You might think that a gas spring would give you exactly that, but they don’t always do so. The more powerful gas springs, while smoother than most steel springs of equal power, still vibrate a lot and require compensation with the hold.

What do we know?
If you believe what I’ve said to this point, then you know what it takes for a breakbarrel spring-piston air rifle to be the least sensitive to hold. It must have the following:

  • Low vibration
  • Short stroke
  • Low recoil

Put all of that together and you’ll have a lower-powered, spring-piston rifle. Time for a short story.

Several years ago, I tested a Mendoza breakbarrel called the Bronco, oddly enough, that was very low powered. It had a strange-looking Euro-styled stock with a too-short pull (about 10 inches) and a hideous kidney-shaped cutout in the center of the butt. The stock was firewood, but the action was good. No, it was better than good. It was great!

The gun cocked easily, had a very short piston stroke, a wonderful crisp trigger and an accurate barrel. I proposed to Pyramyd Air that we have this rifle restocked with a western-style stock, like the old Beeman C1 carbine. They agreed, so I found the stockmaker and had the job done.

We then sent the newly-stocked rifle to Mendoza and asked them to create a model that had a similar stock, though with a pull suited to older youth as well as adults and a couple other important changes. Voila! The Air Venturi Bronco that you all know was born. You can call me an airgun designer if you like, but what I really am is someone who knows what it takes to make the right kind of airgun. Mendoza was already making most of it, but they needed prompting to change those few important details that turned their oddball Bronco, which wasn’t selling, into our Bronco, which is now a best-buy. It’s the same gun, with just a few important things changed. Think of it as the Jeep with the V6 engine that everybody loves, as opposed to the same Jeep with the underpowered 4-cylinder powerplant that someone buys because, on paper, it gets two miles per gallon better mileage. In real life, the details matter.

The Bronco is very insensitive to hold for a breakbarrel and as a result, deadly accurate in the hands of almost everybody. Contrast that with the guy who has to have the absolute last foot-second of velocity, so he buys the air rifle that’s guaranteed to make his life miserable — hard to cock, violent when shot and requiring the skill of a concert airgunner to shoot well. He may have some bragging rights; but at the end of the day, the Bronco owner will shoot a lot more and have more fun doing it.

There are many more stories, but I think my point has been made. You now know how to select a spring-piston breakbarrel that will be the least hold sensitive when shot. Now you know why I went bonkers over the Crosman TitanGP (Lower Velocity) that’s a really fine shooter.

On to other springers
Let’s talk about the underlevers and sidelevers. Within these, there are the underlevers that use a sliding compression chamber, like the Beeman HW97K, and those that have a loading tap, such as the Hakim (made by Anschutz). There are sidelevers with loading taps, as well, but they’re not common. Sidelevers usually have sliding compression chambers, like the RWS Diana 48.

For whatever reason, both underlevers and sidelevers are less sensitive to hold than breakbarrels. Of these, the taploaders seem to be the least sensitive of all, though the TX200 Mark III from Air Arms has a sliding compression cylinder and is also very insensitive to hold.

The hold sensitivity for both underlevers and sidelevers does increase as the stroke length and vibration increase. Notice that I didn’t say anything about the power. The TX200 Mark III is very powerful, yet still very smooth and insensitive to hold. I would describe it as having a shorter piston stroke.

The RWS Diana 460 Magnum, in contrast, has a very long piston stroke and does need a lot of hold technique to shoot its best. The RWS Diana model 48 sidelever has a shorter stroke than the 460 Magnum and is also less sensitive to hold.

It seems that the same things that drive the hold sensitivity for breakbarrels also affect underlevers and sidelever guns. It’s just that these types of airguns start out with an advantage over breakbarrels in the sensitivity to hold.

What does that leave?
I have not discussed any of the other types of spring guns, such as the overlevers (they act just like underlevers) or those that cock via a lever that works in a different way, like the Haenel 310 and the VZ 35. All of these airguns are low-powered enough that they have good characteristics to begin with; as a result, they don’t cause any of the hold problems we’ve discussed.

Other issues
To this point, I’ve said nothing about the quality of the barrel, the breech lockup, or the overall fit and finish of the working parts of the powerplant. These items do affect the performance of an airgun and will break your heart if they’re not taken into account. Some air rifle barrels, for instance, look like 40 miles of rough road and will never deliver pinpoint accuracy no matter what’s done to the rest of the gun. Some barrels are crooked from the factory and can never be fully straightened. You can put lipstick on the pig, but that won’t change its manners!

The bottom line
What all of this means is that no one has to go into the airgun selection process blind. If you can determine the three important characteristics I’ve discussed here — vibration, piston stroke and recoil — you can generally know how difficult it will be to shoot each airgun well.

If you want to hunt with your new rifle, then by all means pick one that has plenty of power. But choose it to use it! Now that you’ve been informed, don’t buy a mega-magnum spring rifle, then whine that it’s too difficult to cock or too hard to shoot accurately.

Many of the veteran readers on this blog seem to keep harping on the low-powered springers for a reason. Guys like Kevin and others keep going back to rifles like the Beeman R7 and the HW50S because they know what wonderful shooters they are. Don’t kid yourself that these guys are not experienced with the powerful springers, too. Most of them have tried the big guns and found they didn’t enjoy all that it took to make them do their jobs.

There’s a place for the RWS Diana 350 Magnum and the Walther Talon Magnum, but some thought has to be given before purchasing either of them or any other spring-piston air rifle of equivalent power. Both rifles are built for a specific purpose, which is hunting. They’re hard to cock and take a lot of technique to shoot to their potential. Neither rifle is the best choice for a first airgun for someone who is either new to airguns or new to shooting altogether.

I hope this report helps some of our newer readers narrow their selections of possible air rifles to purchase next. As always, there will be exceptions to what I have said, but they only serve to prove the general rule.

69 Responses to “How spring-piston rifles behave”

  • Frank B Says:

    This should be mandatory reading for all new customers of Pyramyd Air….for their own good.
    Enthusiasm,tempered with a little knowledge….and you’ll be hopelessly hooked! A plausable uncomplicated explaination of the “Laws” of springer.Well done sir.

  • Don (Gun Doc) Says:

    B.B.,

    I would imagine another thing that is going on right after the piston lands and while the pellet is still in bore is significant waves running up and down the spring like a high speed slinky? Grease, “tar”, or whatever can dampen this to some degree, but at the expense of power robbing friction if you use too much?

    Gun Doc

    • Don,

      According to Robert Beeman, at some point in the shot cycle both ends of the mainspring are free from contacting their normal resting points. So, yes, the quivering Slinky is a good analogy.

      As for damping this movement, close-fitted parts is the most-preferred way. If they don’t have anywhere to go, those springs calm down pretty quick.

      B.B.

  • Ken Says:

    My next airgun may likely be a Beeman R7. Why? Because I started into adult airguns with the RWS 350. I’ve mostly figured out the demands of the Beast (tamed nicely by Vortek), but the experience has me considering also getting a lower powered, smooth-shooting rifle. Experience with my old Daisy 881, Crosman766 and Crosman Model 1 pumpers couldn’t have prepared me for the 9-pound hunk of leapin’ wood and metal that showed up at my door! I anticipate enjoying the contrast in personalities between the 2 guns, and look forward to enjoying a well-crafted sweet and easy shooter, which the R7 appears to be. If one were not hunting or specifically seeking the heavier feel and recoil of a magnum springer, I’d say go for a lower- to mid-power smoothie.

    I would also encourage any shooter to try as many pellet brands and weights as possible, whatever the gun. After owning the 350 for over a year, I’ve discovered a pellet which has taken accuracy to a new level (H&N FTT), greatly increasing my satisfaction with this gun. Keep tryin’ ‘em!

    • twotalon Says:

      Ken..
      The R7 is a nice little rifle. If you want a plainer stock and open sights there is the HW30.
      My R7s shoot in the mid 600s with the Exact RS. It seems to be about the most efficient pellet of those I have tried.
      Noise is pleasant (dull THOOMP) and does not scare the crap out of spooky feathered vermin, unlike the sharp snap that most of my springers produce. Don’t get the impression that I am shooting supersonic with these hotter rifles. It is the quality of the sound that makes them have a sharp snap to the muzzle blast. Not only do the vermin hear it, but it also resonates sharply off of solid objects. They must think they are being shot at from several directions, and will avoid the area.

      twotalon

      • Robert from Arcade Says:

        Know what you mean about that noise. It’s like when deer jump at the sound of the bow string releasing when you shoot at them with a bow. Arrow gets there, but after the deer is gone. Scares them away for awhile also.

    • Bobby Nations Says:

      Ken,

      I actually prefer hunting with my R7 to hunting with my Ruger AirHawk. The R7 is lighter, smaller, and more importantly, more accurate in the field. 7 fpe is plenty to take a squirrel assuming you hit it, and with the R7, hitting your target is just easier.

      • Ken Says:

        Hehe you guys are getting me moving in that R7 direction even more than I already was! I’ll let you know when it happens…just bought a CZ455 .22, so got to spread those purchases out.

      • Slinging Lead Says:

        Ken

        As twotalon said, do not overlook the Weihrauch HW30S. The action is the exact same as an R7 but it comes with the best open sights available for guns anywhere near this price range, while the R7 has no open sights. Also the HW30S is cheaper than the R7.

  • Mel Says:

    There is a very beautiful video that shows the barrel vibration of a springer during the shot:
    http://www.youtube.com/watch?v=FaW_Hs0B79c

    I suspect that breakbarrels springers have slightly more probles with this issue as the barrels are often not 100$ parallel to the piston’s way of travel (the gun has “barrel droop”), and maybe because the barrel’ pivot and lockup allow a little bit more shaking than a fixed attachment.

    • Mel,

      What a perfect video clip that is! It shows exactly what I am talking about. That vibration is the large slow vibration that can be seen.

      Thank you for posting this link.

      B.B.

      • Alan in MI Says:

        Agree – I particularily like the last view at about 16 seconds in. I watched it several times. Note how much the rear sight bounces up and down too . . . .

        And that is with an HW-90, which is probably MUCH smoother than most of the cheap magnum guns.

        Alan in MI

  • RidgeRunner Says:

    I have seriously considered tuning down my CFX. With me, accuracy is far more important than power.

    You might be on to something there Mel. Despite our host’s reassurrances, I will never be able to accept that an air rifle or pistol that has part or all of it’s sighting system on a seperate moving part from the barrel is going to be as accurate as a fixed barrelled air rifle or pistol of similar quality.

    I have been reading this blog for about a year now and the only springers I have been impressed with have been those of high quality and high price. In general, you get what you pay for.

  • twotalon Says:

    B.B.

    I have to take issue with just one thing you said.
    You said that the foreward recoil is what you notice most. Well, I have been punched pretty hard by the rearward recoil with several rifles….even to the point of hurting. But…. I seldom notice the foreward recoil as it pulls away from me.

    twotalon

    • twotalon,

      I have been hurt by springers, too, but never by recoil. Though it came at the same moment as the recoil, the thing that hurt me was the vibration of the stock against my face. The UK-made Webley Patriot and the Beeman Crow Magnum (Theoben Eliminator) were both bad about this.

      B.B.

  • DaveUK Says:

    BB:
    Very informative blog topic.
    Can I talk about this cushion of air that builds up and can possibly create recoil of its own?
    We have spoke before about how on break barrel springers,the air transfer port is off centre to the compression chamber.
    With it being off center,I can imagine all this air piling up unevenly below the transfer port which might create a big cushion of air.
    Bigger than on a rifle such as the TX200 for example,which does have a centred port.
    Do you think this might be at least one of the factors why Breakbarrels are more hold sensitive?
    If so how about these apples?
    Build a breakbarrel where the pivot point is not in line with the compression chamber but below it, so you can centre the barrel and air transfer port.
    I’m not sure but on some real old vintage air rifles it looks like they were designed like that already.
    If that is the case,maybe we should go ‘back to the future’.
    Dave

    • DaveUK,

      Ideas like this are what make airguns so interesting to me. In the firearms world the bulk of opinion goes with what happens to be popular at the moment. Like right now many shooters are enamored with short ads super-short cartridge cases. But shooters experimented with this design almost a century ago and discovered what the shortcomings are. A decade from now some brilliant gun writer is going to rediscover what was well-known in the 1920s, and the world of firearms will veer off in another “new” direction.

      And so it is with airguns, except that because the market is so small, relative to firearms, manufacturers do sometimes listen to their customers. All it takes is one good company to listen to an idea like yours and then implement it, and the entire future of airgunning can be turned on it ear overnight. That is where both the Benjamin Discovery and the Benjamin Rogue came from.

      B.B.

      • DaveUK Says:

        BB:
        I checked back on some old vintage break barrel air rifles.
        They give me the impression of having an inline barrel/tranfer port but in fact they weren’t.
        It is the lack of fore grip and thus the ‘skinny’ look which makes them appear that way.
        I did however find some old ‘Gem’ air rifles.
        The spring is housed in the rear grip at about a 25 degree angle and is cocked by the trigger guard(attached to the barrel block) doubling as part of the cocking mechanism.
        Almost inline I guess.
        Dave

  • Simon Kenton Says:

    What a good technical writer you are!

  • Mikeiniowa Says:

    Tom………
    Thanks for hitting the nail on the head again, now if we could make all the new shooters have to read this…..I shoot the high power stuff down to the R-7 type almost every day at work and while the big boys have their place I really love the low and middle power rifles. As age creeps up on me the high power stuff is going to be shot less and less. I have customers come in and want the fastest rifle on the shelf and won’t take no for an answer until they try to cock them (some custs. can’t). After showing them the difference on the range they soon change their minds, however as many only buy over the net the new customer doesn’t get the feel or know how an on hands shop can provide. Is there anyway you could put this on billboards all over the country???

    • Mike,

      I have already spoken to Edith about making this blog report into an article that stays up and easy to find all the time. The blog is wonderful, but things get buried by the accumulation reports day after day. The fundamentals, like this report, need to remain visible.

      B.B.

  • jgc Says:

    B.B.,

    Since foot pounds came up in your article, I would appreciate your historical insight on the foot pound formula…

    Why is 450240 used as the conversion factor instead of 450436.7?

    7000 grains X 32.17405 pounds per slug X 2 = 450436.7

    The difference in the resulting value is small, but why 450240?

    I await the firestorm of controversy…

    • jgc,

      The constant for the acceleration of gravity is always in flux. It gets changed periodically by the scientific community, and , as you noted, the difference doesn’t matter in practical terms. So we stayed with the old constant from the 1960s. Were we to change, eventually we would be wrong again, and only by a trifle once more.

      B.B.

  • pete zimmerman Says:

    My Nature article comes off embargo at 1:00 PM EDT today. It’s about how DHS became dysfunctional, and what the science & technology directorate has and hasn’t done well. If anybody wants a PDF, post your e-mail here and I’ll make up a single large mailing late in the day.

    pete

  • Don (Gun Doc) Says:

    From B.B. “Since the piston weighs but a fraction of the weight of the whole gun, the gun’s movement is very slight.”

    I think there is an important point here many understand but some will not unless it is stated directly. In another post I showed how little a firearm moves by the time the bullet reaches the muzzle. The small amount of movement of a firearm by the time the projectile reaches the muzzle is a revelation to most people. The movement is so small due to the large ratio of rifle mass to the mass of the bullet+powder. The contrast with what happens in a spring gun is especially revealing in that it rather pointedly shows why spring guns require special techniques maintain accuracy.

    I don’t know how much “the rest” of a typical spring gun weighs compare to the weight of the piston + part of the spring (each portion of the spring moves a different amount, so you have to consider that), but I’m pretty sure the ratio is much less than that of (gun)/(bullet + powder) in a firearm. Thus the “very slight” movement B.B. mentions above is much, MUCH greater than what you get with a firearm. Not only that, but the spring gun then moves forward and even then the pellet is FAR from the muzzle.

    When you consider all this in relative terms, it is no wonder good shots with firearms must to some relearning and readjusting when they begin with air guns!

    Gun Doc

    • Don,

      Pistons vary, of course, but they weigh between one-half pound and just over one pound. The mainspring weighs about half as much, and will vary by more than 100 percent among many guns.

      B.B.

      • pete zimmerman Says:

        This is another reason why precision match guns now all use air or CO2 under pressure as the propellant and not a spring and piston. No matter how good the recoil compensation with either the sledge (FWB) system or the Giss (RWS) system, there is still perceptible gun motion while the pellet is in the barrel. A pre-compressed system, whether single stroke or multiple stroke pneumatic or a pcp has far less moving mass, and so far less perceived recoil and gun motion. BB, today’s post was one of the best; thanks!

        pz

  • kevin Says:

    I agree with Frank. This is an excellent essay on spring guns that is a must read for all air gunners. This article is filled with great information and terrific explanations that should inform potential air gunners about their purchases so they go in with their eyes wide open.

    I’ve never seen this information in such a concentrated form. My education on springers was drop by drop. Devouring books like the Beeman R1 book by Gaylord, reading lots of opinions on the internet, wading through tomes like cardews trigger to target, etc. Added to that was multiple experiences with air guns of different era’s, weight, power and finish and I’ve become a more informed air gunner.

    Coming from a from a firearm background initially I wanted power for pest elimination at a reasonable price. I was looking for value and demanded quality.

    After lots of time and lots of air gun purchases that air guns are not firearms. If I wanted more power in a firearm I bought a well built gun in a bigger caliber that had a reputation for accuracy without catastrophic failure. When I purchased a more powerful springer I realized that typically as power grows so does the weight of the gun, the cocking effort, the tendency of the gun to want to tear itself apart shot by shot and most importantly the difficulty to shoot it accurately grows exponentially. The other difference between firearms and air guns I quickly learned was we have more powerplant choices with air guns. Today, if I need to shoot an 18 grain pellet over 900 feet per second I reach for a Pre Charged Pneumatic (PCP).

    I’ve introduced many of my friends to air guns. After they’re shot a few they realize that an air gun can be a solution to their pest problem, can be an easy and cheap way to hone their shooting skills without driving to a firearm range, can be a great way to bond with your kids while teaching them the responsibility of safe gun handling, etc. As a result, I’m often asked, “What air gun do you think I should buy?” My questions about their primary intended usage, budget, expectations, etc. soon follow. I’m still not comfortable answering the “What air gun should I buy?” question but have realized that it’s also important to pay attention to the car they drive when suggesting an airgun purchase.

    If they have a race car sitting on a trailer outside of their garage that is taken to the track every Saturday and they enjoy working on the car during the week just as much as they do driving it on Saturday they may be a candidate for a magnum springer. I know there are air gunners that enjoy the felt recoil more than accuracy. There’s also a segment of air gunners that must own the most powerful. It’s important for me to know which category they’re in and provide insight into what they’re getting when they buy.

    If on the other hand they want a spring airgun with ease of accuracy along with enough power to take out that occasional destructive squirrel, I have lots of suggestions and many examples for them to try out.

    kevin

  • kevin Says:

    ps-B.B., Thanks for the links in all your articles. This morning I clicked on the link for the Walther Talon Magnum then click on the link on the Pyramyd Air site that said read “Review/article/latest buzz”. The comments in the Walther Talon Magnum – Part 1 review by you in 2008 brought back lots of memories. Among other things, Volvo suggested that Wacky Wayne list his gun for sale on the yellow classifieds. Wayne commented that he followed that advice and listed his first gun on the yellow. I think that was about 100 guns ago LOL! Sure miss comments from Dr G.

    kevin

    • Frank B Says:

      I think your Wacky Wayne estimate is pretty close.Hell,I bought about a third of ‘em.There has never been such an easy sounding,difficult question to answer as “What airgun should I buy?” I too wonder about all the “old” commentors……perhaps they found a cure??? LOL

      • kevin Says:

        Frank,

        But they’re investments right?

        Yes, I cringe at the “what airgun should I buy?” question. I was alluding to it this morning when I ran out of time. It’s like asking, “What car should I buy?”.

        kevin

        • Frank B Says:

          Unless the next plague is squirrels and groundhogs…..yes,they are indeed investments.A saner person wouldn’t drop $6K + on a single airgun(Whiscombe+ 3 barrels) or buy an 8mm Giffard and then
          be content with a pressure vessel that won’t hold Co2……it is around 140 yrs. old after all.
          I would love to find someone competent to reseal it or make an adaptor housing a comparable firing valve.Each tells a special story….maybe I could open a museum for parents to bring the next generation!? How cool would it be to have one where the exibits are allowed to be shot at an indoor range? Beats mini-golf in my opinion.

  • Matt61 Says:

    B.B., so your three qualities of an accurate springer prove the high quality of the IZH 61 beyond a shadow of doubt! I always knew it!

    Now that I think about it, I cannot discern the two parts of recoil for a spring rifle. It does not feel like the backwards force of a firearm, but otherwise, it just feels like a jump more or less in place.

    The business of having the pellet in the barrel during the firing cycle does sound problematic. It makes me wonder if bullets are still in the barrel for semiauto firearms or even artillery pieces. Clint Fowler tells me that his accuracy modification of the M1 has to do with adjusting the gas system so that the bolt does not move until the bullet exits the muzzle. This tells me that most of the time the bullet is still in there but that it is very close to exiting. What about the 1911 pistol and the 105 howitzer? I’m not sure how you would calculate an answer.

    Matt61

    • Matt,

      The bullet BETTER be out of the barrel on a 1911 before the bolt unlocks from the barrel, because the bolt is the slide. If it were to unlock with the high pressure in the gun it would be ruined. The whole genius of Browning’s design was that the barrel and bold stay locked together until the bullet leaves the muzzle and gas pressures drop. Since the slide and barel recoil together for a short period, the bullet has time to clear the muzzle before the link rips the barrel out of the slide.

      I don’t know about the howitzer, except to say that many of them auto-eject the spent powder case and you sure wouldn’t want the breech to open if the high-pressure gas were still in the barrel. So I’m guessing they have also left the muzzle before extraction begins.

      B.B.

      • Don (Gun Doc) Says:

        B.B.,

        Your mention of the 1911 reminds of a signature line I recently saw: “If John Browning were alive today, he STILL wouldn’t have a peer!” Certainly some great “gun guys” have come along, William Batterman Ruger for one, but I do like the quote. And if I had to make a list, for me Browning would unquestionably be #1.

        I need some advice. I am fixing to order some BKL rings for my FWB 124 (awaiting a Maccari kit to get it back up and running.) While I am at it, I am going to try a Crosman 1077 for my “Shoot Where You Look” project. I know I want some Pellgunoil, maybe an extra magazine, and some12-rd clips. Now, for pellets. If I were going to take advantage of the four-for-three deal and were buying two tins for the FWB 124 and two tins for the 1077, what four tins should I buy? Perfectly acceptable to me if there are repeats in suggestions (or not.) I am willing to buy better quality pellets. I realize this is just your best guess, as some good suggestions may not work well in my guns, but who better to make a best guess than you?

        Thanks,
        Gun Doc

  • Wulfraed Says:

    Diverting the thread somewhat…

    Could we please force educate journalists…

    http://www.dailymail.co.uk/news/article-2034464/Shayne-Riggleman-kills-murder-spree-shooting-himself.html

    Their prime photograph is a paintball gun!

    • pete zimmerman Says:

      I don’t know how to educate journalists, or anybody else, I think. The paper editor at my former place of work wants me to explain that there are 1,000 kilos in a mega (kilotons and megatons in this case). All I responded was that I was not in the business of explaining the metric system to ignoramuses.

      • Wulfraed Says:

        Ouch…

        I could understand needing some explanation in the financial realm since, as I recall, the US scale runs: thousand, million, billion, trillion whereas UK scheme is: thousand, million, thousand million, billion.

  • JohnG10 Says:

    Great article – Truly awesome !

    I would really like to see a “Part II” that shows how much differences these factors make in practical terms. ie: Is an “average shooter” likely to see 1/4″ group size differences or 3″ group size differences due to all the “ease of shooting” factors you mentioned in today’s blog ?

    You could fire five 5 shot groups at 25 and 50 yards with a handful of “representative” rifles, and report all the group sizes. Then new airgunners would have a way to decide if the extra weight and loading difficulty of an underlever are “worth it ” versus a break-barrel, or whether the hassle of carrying a pump or air tank is “worth it” to them.

    I nominate the following “representative” rifles for “Part II”:
    RWS 34 (Typical 1st “quality” breakbarrel)
    R9 (Typical “extremely accurate” breakbarrel)
    TX200 (Typical “extremely accurate” underlever)
    Marauder (Typical 1st “quality” PCP)

    If you need any testers – I’d be happy to volunteer !

    John

  • CowBoyStar Dad Says:

    A great article. As others have said, this one, along with a few others of its ilk would make a fine book.
    Here in Edmonton it is usually the start of fall about now…temps around 20C (about 68F), plus it’s starting to get dark about 8PM (vs 10:30 a month ago).
    But we’re having an unusually warm Sept and today was 30C (about 87F).
    And absolutely no wind.
    After reading today blog I figured I just had to…had to drive out to the range after work. I picked up my Slavia and a selection of pellets as soon as work ended, and, after 1 hour drive was at the range by 6:45PM leaving me an hours worth of perfect shooting weather.
    I tried to remember everything B.B. said in the above blog, plus everything else I could remember that he has said about springers.
    I managed 7 10 shot groups (with a few sighters between changing pellets). Lo and behold the Hobby’s were easily the most accurate, even better than the Exacts I figured would be my goto pellet with this gun. In the past I just didn’t figure a wadcutter would work well at 100′…maybe it’s because their lighter weight works well in a low-powered springer, but I was rewarded with 3 groups that were under an inch, sitting, unsupported but using the artillery hold (as best I know how).
    Personally I feel that’s pretty good (for me anyway)…consistent 10 shot 1″ groups at 100′. I wouldn’t really try and kill anything at that range with the power of the gun…but at least I feel confident that if I absolutley had to put a bit of food on the table I could do it.
    Just a damned fine evening.

  • Sal P Says:

    I disagree with your implication that break barrel spring guns are the more difficult to control than under levers.

    If the piston weight, diameter, travel speed and pellets are the same in a break barrel or under lever, then the recoil will be the same. The vibration depends on the dimensions and weight of the various components, but NOT inherently on the cocking mechanism.

    • Sal P,

      I only say that because it is true. I’m not guessing about this. I have seen it repeated thousands of times (I have competed in several airgun sports, plus I test airguns all the time).

      Like I said, I don’t know why it is this way, but I do know that it is.

      B.B.

      • CowBoyStar Dad Says:

        good on ya b.b. (for telling it like it is).
        I’m always amazed when someone post for (what I assume is the first time…I’ve never seen the Sal P’s moniker before) the first time…not with a ‘hi guys, new hear’ or ‘first timer, just wondering why’ etc, but instead with both barrels firing.
        Some people on the ‘net really need to learn a few manners.

  • Frank Says:

    How does the New Bronco compare with the Mendoza RM200. In past posts it has been mentioned that the Bronco is the RM200. But you state that there are some modifications that you suggested.
    I was wondering because my 200 in .22 shoots around 500 but not as accurate as I would hope for. Very pellet fussy. You may not want to mention them, but what are the changes? You don’t need to cross any bridges.

    Thanks, Frank

    • Frank,

      I don’t think I have ever said the Bronco is an RM 200. If I did, it was a mistake, but I don’t think I said it.

      The Bronco is an RM 10 — a rifle Air Venturi decided not to import because of the horrible stock.

      Beside the stock, the Bronco also has no oil hole on the spring tube and the muzzle break is twice as long as those found on Mendoza rifles.

      B.B.

    • Vince Says:

      Frank, I had an example of each torn down side-by-side. Mechanically the guns are very similar and had the same powerplant bore/stroke (25.4mm x 48mm). But the RM200 spring was different, being about 10% stiffer and having about 11/16″ more preload than the one in the Bronco.

  • Frank Says:

    Sorry Tom, no you did not say that. What I should have said was that it was mentioned on other forum posts. As for the oil hole, I don’t use it on my 200, and think about 500 fps is about right for it.
    Thanks again, Frank

  • Billy Says:

    An excellent read. I actually came to the same conclusion about piston stroke, but the the bit on vibration was very enlightening. Would it not therefore be wise to use thick diameter chambers for air rifles so that the stoke can be shortened appreciably. My old Gecado 35 has a 28 mm inside diameter and 70 mm stroke. By comparison my Mendoza RM 800 has a 26 mm inside chamber but 80 mm of stroke. A quick calculation would lead a person to the conclusion that even though the Gecado has the smaller stroke, it actually has the slightly greater volume. I also do like the other repurcusions of a shorter stroke despite the reduced dwell or lock time. One of them is greater preload on the spring, thereby allowing greater pressure when the piston is at the end of its stroke. The other advantage I like is the increased leverage on the spring thereby making it more user friendly and easier to cock. what would be interesting is to see how much smaller a person could actually make the chamber without affecting power. A look over at the volume versus power ratios seems to me to be very enlightening. The Hw 80 or I think you you call it the Beeman R1 actually has quite a bit smaller swept volume than more modern magnum air rifles yet I would say that there is very little if any difference in power but the R1 wins hands down when it comes to versatility, ease of use and accuracy. JUst a thought.

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