Why are some spring guns more sensitive than others?

by B.B. Pelletier

Let’s look at a question posed by Dave on Friday.

“I was wondering why different spring guns need different holds. Is there really that much difference in how they are manufactured?”

Good question, and I like giving the answer, because it explains so much about airguns – and everything else!

Yes, there can be a lot of difference in how airguns are manufactured. There is also a huge difference in how they are designed, which also affects how hold-sensitive they may be. Before I get to that, let me tell you a short story that will illustrate my point.

Formula Vee racing
A friend of mine was into Formula Vee racing. That’s a poor-man’s Formula Three car powered by an air-cooled VW engine. Although I said “poor,” it’s easy to spend more than $50,000 on the engine and car – so it ain’t cheap. Because the engines are small and low-powered, the speeds are slow, compared to Formula Three.

My friend built engines for these cars. His engines always performed a little better than all the others, which kept him in demand. His competitors wanted to know his secret, which he never told them but did share with me. When he built an engine, he kept the specifications as close to the limits as possible. He blueprinted the engines, which not only meant their tolerances were tight, but also all moving parts were balanced to the gram! When they revved, they were smoother than the engines of his competitors. They got up to speed a little sooner and revved a little higher than all the other engines. And, that, in the hands of a good driver, won races!

The same is true for airguns. A “1000 f.p.s.” airgun that recoils and buzzes when it shoots will throw pellets all over the place compared to a smooth-shooting 900 f.p.s. rifle that feels like a safe door closing when it fires (yes, there are such rifles). But, power doesn’t have to go down for performance to go up. A stock .22-caliber Beeman R1 gets about 17.5-19 foot-pounds of muzzle energy. It vibrates some and kicks a lot. When the legendary Venom Mag 80 Laza tune was applied, the power rose to 23 foot-pounds, while the vibration stopped completely and recoil dropped to the same level as a Beeman R7. A rifle with that tune would actually shoot better than a factory R1 – just because it was easier to shoot the gun. That’s what can be done with a good tuneup.

Now, the manufacturer can also do this to the gun before it leaves the factory. That’s exactly what John Whiscombe does with each of his handmade air rifles. They’re in the highest state of tune when they leave the factory. All the hand work that goes into that tune drives up the retail price of the basic gun to $3,500! Wouldn’t it be nice if someone would design a gun that could be built right without the need for all the hand work? Well, someone has!

Air Arms has designed a spring gun that goes together quickly and still delivers wonderful performance. It’s the TX200 Mark III. Please don’t write me to ask if the TX200 Hunting Carbine or the Pro-Sport are just as good as the regular TX200 Mark III, because I am telling you right now they aren’t. The TX200 is perfection. The other two fall short – though not by a lot.

Other air rifles are compared to the TX200 both in terms of smoothness and insensitivity to hold. The HW77 and HW97 are pretty close. Both can be improved with tuning. There are other rifles with increasing sensitivity that are still considered not too sensitive. However, breakbarrels, as a design style, are always more sensitive than underlevers and sidelevers. They can be just as accurate as the others, but they nearly always do require a lot of special handling technique to shoot accurately. Just why this is, I really don’t know.

Here’s what I do know for certain.

1. The less a rifle recoils and vibrates, the less hold-sensitive it will be.

2. Rifles of the same model tend to be alike. If one Beeman R1 is hold-sensitive, they all are. Only by tuning can you make a difference in one specific rifle.

3. Rifles of similar build characteristics tend to perform similarly – which is why I don’t have to test each and every model of Gamo to know how they perform. One time I got bitten by this generality, though, when I tried to estimate how the Gamo CF-X would perform. It surprised me by out-performing my estimate. In general, though, rifles of similar builds perform similarly.

So, Dave, there are lots of reasons why different spring guns perform differently. However, you now should know that they aren’t all unique. There are ways of generalizing.

30 thoughts on “Why are some spring guns more sensitive than others?

  1. Hi B.B.!!
    Reading your comments about the TX200 just reminded me of a question that arises from time to time: does a UK – 12 ft/lb TX200 have “the same” action as a FAC TX200? I mean, other than the mainspring, are there any differences?
    Thanks!
    Rod.



  2. B.B.,
    You keep providing me with more “reasons” to “invest” in a TX200. I don’t know how much longer I can hold out.
    Thanks for a concise explanation on a subject that has been baffling me, too.
    I’ll admit I’m having fun (and frustration)trying to smooth out my Gamo Shadow with various internal changes, and am having some limited success with this science project. But you can’t make a silk purse out of a sow’s ear.
    Pestbgone


  3. B.B., about a UK-TX200:
    The piston is different…. You mean, is it longer? thus, when you cock the rifle, it engages sooner? (The overall movement of the lever is less than in a FAC rifle?).
    thanks!
    Rod.


  4. Rod,

    Yes, it is exactly as you envision. Less air space means less air to compress, which translates to less power. It makes sense when you ponder it, but it isn’t the first thing people think about.

    Sometimes the cocking linkage is also altered to keep the leverage approvimately the same, but when the Air Arms Pro Sport was first put on the market, the UK version was harder to cock because they used the same mainspring as ther FAC gun and didn’t bother changing the cocking linkage.

    B.B.


  5. Pestbgone,

    No, you cannot make a silk purse from a sow’s ear, but there are airguns that have great potential that has not been fully realised by the factory. The R1 is one example.

    The TX200 Mark III is about as refined as an airgun can become. I have never seen a Mark IIi that was improved in any way by an aftermarket tuner. The Mark II guns had some room to grow but not the Mark IIIs.

    B.B.


  6. bb, as long as i hold the underlver rod back with my left hand after cocking, as I load a pellet with my right, I NEVER have to worry about losing fingers, right?



  7. The way you describe loading is the prescribed method for all airguns having sliding compression chambers. The TX200 is designed in such a way that this method is not strictly necessary, however, if you load that way you will never have a problem.

    B.B.


  8. B.B.,
    Thanks for the comments. And reading between the lines, when I get my TX200, I will keep my hands out of it and not try to “make it better.” Hopefully I will have gotten that out of my system on the inexpensive guns.
    Pestbgone


  9. BB
    I got the TX200 HC .22 just because Pyramyd was out of stock of the Mark III for 2 months and I got tired of waiting. I have nothing to compare it to except my CFX, so I think my TX is perfect. If I hold it tight or rest it on something, my groups double in size. As long as I rest it in my palm I can hit a nickel at 20 yds every time with FTS. Hope to be able to compare it to a Mark III some day.
    Pestbgone – Sticking your finger into the breach without holding the lever back would be like sticking your head in a crockadile’s mouth while his heart is still beating. The anti bear trap is probably 100%, but…would you want to change your handle to Stubby? Go for the TX – you won’t regret it.
    MCA


  10. A very interesting post. I see it’s powerful but not a “Ultra Fast Magnum” which isn’t needed anyway. Accuracy is the key. If I want more than 900 in .22, I’ll get out my .22 LR or something bigger.

    Last night, I got rid of a squirrel
    that wanted to live in my garage.
    All it took was six pumps in an old benjamin 347, .22.


  11. bb,

    thanks a bunch for the post, i really appreciate it. i like knowing as much as i can about airguns, and you constantly help me to do so.

    Dave


  12. BB.

    You have said that you prefer the tx200 over the hw77 because its smoother, etc. How much less smooth is the hw77?

    I like the hw77 because it has got open sights, its ambidiextrous and is cheaper.

    If I always hold the underlever while loading, will my fingers be safe in the hw77?

    Also, what mount do you suggest for mounting a Leapers 8-32×56 scope, considering the tube is 30mm wide and the width of te scope rails.
    Will this scope, that is 16.5″ long cover the loadind breech?
    Thanks
    Alex


  13. bb,

    what is it about spring guns that make them “twang”, and what is it about the more expensive guns that make them not “twang”, or have less “twang”?

    Dave


  14. bb,

    also, i know there have been plenty of discussions on which pellets should be used to not destroy a spring, so my ? to you is in a 1000 ft per second springer, how heavy of a pellet can i use without worrying about the spring losing any life. can i use crosman 10.5 premiers, and kodiaks, or should i stick to around 8.5 grain pellets?


  15. Speaking of 1000 fps rifles, do you know of a good one for around, or less than $200, that has sights, but can also have a scope mounted? I like the new varmint hunter, but it doesn’t have any sights on the rifle it self. I enjoy shooting with a scope, but also with only the regular sights sometimes too.


  16. BB.
    One more question, how wide is the dovetail on the tx 200, do 3/8 ” rings fit, what rings do you recomend for a 30mm fube scope.

    Alex


  17. Hi BB,

    Thanks for the info on keeping your fingers intact. I was loading my reworked TF99 (better, but still needs more tuning) and my $20 B-3 improperly and could have lost part of my left thumb and forefinger. Never even thought of that until you said something. I now hang onto the levers and barrels of all my guns while loading. My fingers thank you again for keeping them whole, and I thank you for a wonderfully informative blog.

    Another /Dave



  18. what mounts would you recommend for a gamo 440? I have a cheaper simmon’s scope that i want to mount. Do you think the gun will shake the scope to death?


  19. Alex,

    The HW77 is 17 percent less smooth than the TX200.

    Seriously though, if you like the HW77, your decision is made. Stop comparing it to a rifle you don’t want to buy. You have good resasons for liking the 77, and it is a nice air rifle, so forge ahead and get the gun you want.

    You MUST hold the underlever at all times when loading the 77 because it does not have any mechanism other than a trigger-based lock to prevent premature closure. The TX has a mechanical ratchet lock.

    The mount you get must be 11mm (or 3.8, in the case of Leapers – they fit 11mm dovtails as well). and it needs a vertical scope stop pin.

    Yes, the scope will probably hang over the loading port – especially if you use the sunshade.

    B.B.


  20. Dave,

    Vibration is what makes the twang and closer tolerances is what reduces it.

    Use whatever pellet you want – weight has no bearing on spring life. But pay attention to accuracy and to vibration that will differ pellet by pellet.

    B.B.



  21. R10,

    Poor condition covers a lot of territory. As long as it’s just cosmetic and not mechanical, an R10 should still be worth $150. But if there are broken parts, the price drops to very little. The barrel is always worth $50 and so is the stock. The Rekord trigger should bring about that much, as well, so it might be best to part out a broken gun.

    B.B.


  22. Simmons scope aren’t the best, just like BSA. On the low end, they are made more cheaply than many other Chinese scopes these days. So, yes, a Gamo 440 might destroy a low-cost Simmons.

    As for mounts, if you have the Gamo scope stop plate, any two-piece mount will work. The Accushot mounts are low-priced and good quality. Get the ones with 4-screw scope caps.

    B.B.


  23. bb,

    arent the scopes you get with gamo guns bsa’s? so, they send you a scope that their gun will destroy? some things about gamo i like, for example, the air shotgun(btw, i wrote a suggestion to the company on making a new shotgun with the 1250 powerplant, and they said they will start making designs), but some things like the customer service, and the fact that they sell you a scope that wont work, just irks me.

    bb, another ? regarding gamos…is there any way to tune an airgun to make it more accurate(since the gamo break barrels arent the best)…i like their designs, but not their performance. or do you think it would be possible to rebuild a gamo(like the extreme) and put in a more accurate barrel, better trigger, etc.? or is it not suggested, like tinkering with the condor, which tom gaylord said to stay away from if your not a proffesional, which i am not.

    thanks for all the advice,

    Dave


  24. Dave,

    Tuning seldom improves accuracy. All it can do is make it easier to shoot a gun accurately, but accuracy lives in the barrel.

    You won’t find any replacement barrels for a Gamo breakbarrel that will improve accuracy.

    If you want accuracy, here are the affordable springer brands that have it, Weihrauch, BSA, Webley, CZ and BAM, Air Arms, Beeman (but only the R-series and HW brands), IZH, and RWS.

    B.B.


  25. Ok when it comes to accuracy i get Weihrauch and RWS because they are german heritage. i understand Webley and Air Arms for their heritage from england. IZH and CZ i can understand.
    what i don’t understand BAM in this group because chinese are not known for their barrels. are the barrels made somewhere else (germany/england) and they are just manufactured in China? since it is a replica of the TX200, does it have the “bear-trap” safety mechanism?
    concerning Beeman i thought their manufacturing was farmed out to China also. are the R and HW series made elsewhere besides China, which is the reason why you included them?
    and who is BSA?
    thanks for any information


  26. You need to read my test of BAM B40 rifles.

    Beeman R-series guns are made by Weihrauch, and HW stands for Herman Weihrauch – so both are made in Germany.

    Who is BSA???!!! Birmingham Small Arms.

    Well, they used to be a world leader in firearms technology. They have supported the British empire with firearms and other durable goods since the middle of the 19th century. Their barrels are among the most accurate in the world. They have fallen on hard times of late, and don’t let the fact that Gamo owns them color your opinion. BSA is still a premier airgun maker.

    They are poorly represented in the U.S. today, but BSA is the company who, in 1906, invented the modern spring piston air rifle.

    B.B.


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