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Education / Training Why powerful mainsprings don’t always increase velocity

Why powerful mainsprings don’t always increase velocity

by Tom Gaylord, a.k.a. B.B. Pelletier

Today’s report is the one I mentioned forgetting in last Friday’s blog! Blog reader Errol reminded me about it yesterday.

I hear this so often from airgunners — how they think they’re going to add a more powerful mainspring to their airguns and increase the power. It sounds logical, but it often doesn’t work; and it nearly always doesn’t work as well as you think it should. Today, I want to discuss why that is.

Fact 1
The Weihrauch HW 35 was always considered to be one of the most powerful airguns in its day — which was the 1950s. They delivered over 700 f.p.s. when new in the 1950s; and over time, this rose to 750 f.p.s. Careful tuning could get close to 800 f.p.s. from certain guns. This model is still being made today, but now it sells because it’s so pleasant to shoot and doesn’t produce excessive power. How times change!

The HW 35 was so-named because the length of the piston stroke is 35mm. Piston stroke is the distance the piston travels from being cocked to being at rest at the end of the firing stroke. When Robert Beeman set out to make what eventually became the Beeman R1 rifle, he used the HW 35 as the starting point and increased the piston stroke to 80mm. And that’s where the additional power comes from — the piston stroke length and not the strength of the mainspring. Greater stroke length means greater swept volume, which means more air to compress for the shot. It doesn’t matter all that much how fast the air is compressed, which is the only thing a stronger mainspring does.

Fact 2
Then, there’s the story of the man who wanted to build a supersonic .22 pellet rifle. So he took the Beeman R1 as a starting point and built one that was 125 percent larger. The late Steve Vissage built a Frankenstein rifle that I documented in a report called Steel Dreams. It weighed 11 lbs., took 53 lbs. of force to cock and was larger than the R1 in every way, save one. It developed the same power! Yes, bigger mainspring and wider piston did not increase the power of the gun one iota.

Why is this true?
I know you want an explanation of why a more powerful mainspring doesn’t necessarily increase power. Here it comes:

THE MAINSPRING DOESN’T ACT DIRECTLY ON THE PELLET

The mainspring pushes the piston. The piston compresses air in front of it, and it’s that compressed air that gets behind the pellet and pushes it up to speed. The mainspring never touches the pellet. So, changing the mainspring has no direct effect on the speed of the pellet.

Here’s a good example everyone will understand. We have a house with a hollow-core door as the front door. Forget the fact that it violates all building codes — your cheap Uncle Rufus put it on when the old front door finally broke. This one was dirt cheap, which is why he got it. But your Aunt Thelma is justifiably worried about a break-in; so when Rufus is out of town, Thelma has a locksmith install a super-duper triple deadbolt lock on the door. Is that going to protect her? Of course not. Any burglar can simply break the door apart with one good kick. The lock will still be secure, but there won’t be any door attached to it.

Do any heavy mainsprings ever work?
Am I saying that heavier mainsprings never work? No, I’m not. When I was testing the Beeman R1 for my book, I installed the Mag 80 Laza Kit from Venom in England. Ivan Hancock created a drop-in kit of parts that worked well in the R1/HW 80 and increased the power. The mainspring was a very long stiff spring with thicker wire, and it was coated with a black tarry substance that I named black tar in my newsletter articles. That’s where the term black tar comes from. Black tar is also called velocity tar in some circles.

The R1 went from requiring 36 lbs. of force to cock to 50 lbs. with this kit. But the heavy mainspring was not directly responsible for the power increase. The kit also included a new piston that had 6 synthetic bearings that are now called buttons. These buttons rode against the spring cylinder walls and kept the steel piston from touching the steel spring cylinder.

Here’s the deal. The new piston was harder to slide inside the spring tube because the synthetic bearings pressed tightly against the sides of the spring tube. The powerful mainspring simply brought the piston’s speed back to parity with the factory piston. What increased the power was a combination of a better piston seal and the elimination of all piston vibration when the gun fired. The gain was just a few foot-pounds of energy, but the rifle was now getting everything the R1 design could possibly give.

A parallel in the pneumatic world
Most of you readers are aware that pneumatics work within pressure limits, and over-pressurizing them doesn’t add power — it takes it away. The reasons are different, but the end result is the same as for heavier mainsprings. The design of the gun is being overcome by one thing (the mainspring in a spring gun, or too much reservoir pressure in a pneumatic) and the performance balance is tipped toward the negative.

CAN a heavier mainspring increase the power of a springer?
Yes, it can if you also change the rest of the powerplant along with the mainspring. And no, it won’t if a heavier mainspring is all you add. The secret to more power is to balance all the components so the gun performs at its optimum. With all airguns, there’s a limit to how far you can go. Where that limit is depends on the rest of the design — the parts that are too expensive to change.

You can break your heart trying to buff up a dirt clod to a high shine. Or you can start with a gun that has some potential and make real progress by artfully changing the things that matter. The secret is to know which is which.

One last remark
Pyramyd AIR is stocking the most recent issue of Airgun Hobbyist magazine. If you want to try just a single issue to see if a subscription is worthwhile, now’s your chance.

author avatar
Tom Gaylord (B.B. Pelletier)
Tom Gaylord, also known as B.B. Pelletier, provides expert insights to airgunners all over the world on behalf of Pyramyd AIR. He has earned the title The Godfather of Airguns™ for his contributions to the industry, spending many years with AirForce Airguns and starting magazines dedicated to the sport such as Airgun Illustrated.

56 thoughts on “Why powerful mainsprings don’t always increase velocity”

  1. Dear B.B.

    Thank you so much Sir, much obliged. Man do I feel stupid!. What an education I’ve got here. And all this time I’m thinking BIG mainspring BIG power.Never thought so much was involved, but you put it so well NOW AH SEE THE LIGHT! Am I GLAD I joined this Blog. There is so much more to learn. Liked that bit about Uncle Rufus & Aunt Thelma LOL. You have such a fun way of getting your point across it sticks in the mind. Many thanks once again.

    Errol

  2. B.B.

    And I would also like mention – besides a non-linear and unlikely increase in velocity (power) larger spring almost certainly means a decrease in accuracy. There are several reasons, but the first one is sharper and more powerful kick (pellet leaves springer’s barrel after the piston hits the front wall of the cylinder), increased mass of moving parts (powerful spring means more mass to be put at the piston) etc. A medium-powered hit is way better than a armor-piercing miss 😉

    duskwight

    • caveman,

      That depends on where exactly and in which form you put this all this gas. More fuel-air mix into your engine – and it’ll do. A good deal of fuel into right spot can even make your car fly, well, at least once 🙂

      duskwight

      • I’ve been wondering about this. On my trip, I saw a movie called Fast and Furious: Tokyo Drift about which I will have to say more at another time. Anyway, it’s all about fast cars, and these guys have switches they throw which dramatically increase the speed of the car–up to 197 mph in one case. This is also reminiscent of a scene in the iconic Road Warrior movie. The chief villain is a bodybuilder wearing a hockey mask who calls himself the Lord Humongous. His power lies not just in his muscles, or in his .357 magnum, but in a special car equipped with canisters of gas. He throws the switch to these tanks and his car takes off with an acceleration that the Lord Humongous himself can barely tolerate. This car will even outrun Mad Max’s police V8.

        I don’t know if altering an air-fuel mixture could do all this. I seem to recall that the mysterious gas canisters contained some kind of nitrogen mixture. That is reminiscent of some of our discussions about whether different gases can propel pellets faster.

        Matt61

        • Matt,

          That’s N2O, nitrogen oxyde (I). Works this way – cools down incoming air-fuel mixture (and cylinders as well, giving better compression) and degrades releasing oxygen, thus rising fuel/oxidizer coefficient (air has only 21% of oxygen) as a result giving faster and more efficient burning.
          Another take on the same tune is nitromethanol CH3NO2 – which is quite a good fuel by itself, it can burn almost without oxygen (it has oxygen in itself) and having a higher laminar burning speed it allows for a faster piston cycle.

          duskwight

        • And they refer to it as “noss” in the movie because one of the biggest seller of bottles and system is called Nitrous Oxide Systems “NOS” with their signature blue bottles.
          It used to be the power adder of choice but turbos is gaining in popularity everyday.

          By the way madmax with his switchable super cherger is a fake. It doesn’t exist but it would be ideal, fuel economy by day and mucho power at night for the street races.

          J-F

        • Nitrous Oxide requires pressurized storage tanks, and an injection system. Storage tanks run out…

          Max’s Interceptor was rigged with a supercharger — it does take some power to drive it (Turbos are run from exhaust gas flow, supers from a drive belt). His switch just activated a clutch to engage the supercharger. Presuming the engine had been tuned for the increased air/fuel mix (typically, by /reducing/ the compression ratio), he had the longer endurance. [Normal engines run with a manifold /vacuum/; my old Laser turbo ran at -7psi, when a non-turbo ran more like -14 to -20psi. At full boost, it would be positive at 11psi; superchargers should be similar — but with less lag]

            • Kind of not true if you have the air fuel mixture correct and also the spark timing.

              Nitrous oxide allows for a more condensed fuel mixture. The mixture goes in lets say the size of a marble then when the spark makes the mixture explode it turns into the size of a basket ball.

              More power.

              Depending on how big of mixture that goes in can definatly make things break. Been there done that.

          • Some superchargers are overdriven and some are underdriven. Usualy the smaller 172 cubic inch roots style blowers are positive and the bigger 671 and 871 style blowers are negative driven.

    • If I put more gas in my car will it go faster?

      Overall… No… You have to burn more fuel just to move the mass of the additional fuel.

      If, however, you mean what has been mentioned by others [super/turbo charging] — increasing the air/fuel mix that enters the cylinder — quite likely… As long as you avoid pre-ignition (knocking) — which normally requires both the use of premium grade fuel [which, contrary to many folks belief, does not improve performance for vehicles that run okay with regular — it is actually harder to ignite, and is required by high performance engines for that reason, as they will cause pre-ignition with regular]

      Ford’s current “Eco-Boost” engine is nothing more than a revival of the turbo-charger; something Chrysler phased out years ago (one Chrysler innovation was a water cooled turbo, which made them a bit more reliable over those that just used bearing oil to cool the rotor — which could cook the oil if the engine wasn’t give time to cool off before shutting down). For comparison data: The 2l engine in the first generation Plymouth Laser RS (Mitsubishi Eclipse; joint factory) was only 145HP (or was it even lower, 135) with a low torque peak at 5000rpm [short stroke quad valve DOHC engines like high RPMs; unlike the long stroke 6-cylinder in my Jeep], HP peak at 6000rpm; the turbo version was 190HP at 6000rpm, and 205ft-lbs of torque at a relatively low 3000rpm — a much wider power curve. Putting it in airgun terms, the non-turbo would be a customized Bronco [since the real one doesn’t have the needed tuning options] set up for maybe 700fps within, say, 1800-2000psi [a narrow range]; the turbo is more a Marauder running 900fps over a range of 2200-2700psi.

  3. B.B.,

    What might a more powerful mainspring do for an air-rifles velocity consistency? Better? Worse? Same?

    Are there any benefits to adding a more powerful mainspring?

    Victor

    • Victor,

      Besides the Venom Mag 80 mainspring I mentioned, I haven’t seen too many more powerful mainsprings that actually helped the gun. I guess a couple of gas springs did, but that’s about the full extent of it.

      B.B.

    • Victor,

      The “mainspring” is just one component in the equation that results in a springers velocity consistency (inconsistency?). I would submit that the spring, whether weaker or stronger, is a minor variable in narrowing the velocity spread in a springer.

      A perfectly round tube, correctly sized piston seal, good breech seal, correctly tensioned lock up (whether it’s a ball detent or chisel detent doesn’t matter) are among the factors that I would consider higher priority in narrowing the velocity spread in a springer.

      kevin

      • Kevin

        Absolutely agree, but would like to add a good piston seal to prevent back airflow between piston and tube. If all air is compressed and sent to a good breech seal the firing becomes a lot softer and powerful
        For the mainspring i usually add some washers to add some pre-tension, but proper sealing both sides of the seal and adding more air volume (reducing piston head) gives a much better output

      • Kevin,

        I haven’t given any of this much thought, probably since I’m not much of a tinkerer, but what you say makes sense, as does what B.B. says. A good seal(s) is more important, among other things as you mentioned.

        Victor

  4. That’s perfect timing!
    Someone on the Canadian Airgun Forum was asking last week if he could ad a spring around the rod of his nitro piston rifle to get more power out of it.

    I still have a question about this thing. Why did Relum (and possibly others?) Use two springs one inside the other to power their rifles? Was it for marketing hype, for ease of cocking, to use cheaper springs?

    J-F

  5. A JM spring did not boost the velocity over the factory spring in my Diana 23 but it fits the spring guide more closely and it operates without any buzz.

    A Titan OX spring in a Haenel 303 did produce a noticeable jump in power – 50 fps or so – but the firing behavior was much harsher and the cocking effort almost doubled. Not worth the increase at all. Back to an OEM spring for the 303.

    Paul in Liberty County

  6. I found a Relum Telly at a yard sale a little wile ago It needed a new leather piston seal. I made a new seal then I found a site http://www.airgunspares.com that sells Relum replacement parts. My Telly only has 1 spring but the replacement spring kit has 2, would it make my Telly work better(smoother cycle more power better accuracy) with the 2 spring kit or should I just leave the 1 spring in it

    • James,

      Vince is our expert on the Relum Telly. He wrote a guest blog about it that addresses the spring situation. Read that and I think you’ll get the answer you are looking for:

      /blog/2012/12/the-relum-telly-part-2/

      B.B.

    • It seems that in the Relum Telly, the inner spring serves as a guide for the outer spring. The one I worked on had a rougher cocking cycle when I tried removing it. Since the springs are counter-wound there is no real issue of binding, and (believe it or not) that inner spring does materially contribute to the gun’s power.

  7. This is what I do with airguns. I don’t worry about the mainspring. In fact I don’t deal with springers when I tune a gun. I deal with the pneumatics. I don’t like the idea of dealing with a spring under pressure. I increase valve openings so more air gets behind the pellet, get the pellet a bit farther in the breach so it catches more air more air as efficiently as it can. Pump guns get a flat top piston/valve unit to provide a bit more volume per pump into a larger air chamber in the valve assembly. I add a power adjuster so I can get the striker to hit the air valve a bit harder and hold the valve open a bit longer to let a bit more air behind the pellet. Everything is about putting that air behind the pellet and how much can I put there. At this time I have a Discovery in .22 performing about as good as a Marauder but without the shroud which is a bit hard to get in Michigan. It’s easier to take what I got and make it what I want.

    BB is right. everything regardless of the type of gun has to do with how much air you can put behind the pellet. But you can only go so far before. Once you reach the top of what is physically possible everything else you do will have a negative effect on your gun. I’ve tuned several guns to the maximum possible then the guy I tuned them for tries to exceed what I did end up breaking the gun then either blame me for their blunder or blame the gun for failing to perform the way they think it should perform. So I see why air gun manufacturers tune guns at the factory to fire a bit below their maximum possible. It’s a measure if idiot proofing the gun since they know somebody is going to try to make the gun exceed the specs of the gun. That way there is a little bit of safety.

  8. Fascinating. It is so tempting to think of the mainspring pushing the piston faster which pushes the air faster. The business about stroke length and swept volume is reminiscent of how a longer stroke is more effective than a shorter in swimming, rowing, kayaking. Maybe there is some underlying concept of fluid dynamics at work.

    B.B., interesting about the M1 carbine. As to its lethality, how does the .30 carbine load compare to a .357 magnum? I would guess that it is somewhat less, but if it’s anywhere close, then it would have some capability. I’ve heard policemen say that when using law enforcement loads, they’ve never had to shoot anyone twice with an M1 carbine.

    Mike, I imagine a double-feed as loading a round on top of one that is already in the chamber. Certainly extraction could contribute to this problem. Kyle said that the SEALs found that the problem was related to the dust cover and when they kept that closed, a lot of the problem went away. Right you are about softpoint and hollowpoint loadings for the 5.56. No argument with that. But I was thinking of the other common response that power can be compensated for with shot placement. That is true in principle. But I wonder if this idea has been adapted from hunting and target shooting in a way that is potentially misleading. In combat, your target will be dodging around. You too should be moving or looking to move–as our hapless special agent in Hawaii found. I don’t know how realistic shot placement is in a combat situation. Even Kyle, the ultimate sniper, said that his sniping shots were made to center of mass rather than a smaller target. How much more true of ordinary mortals in combat which would seem to throw a lot of shot placement out the window however desirable it might be.

    Wildey, is an AR10 a specific model of a .308 rifle or a generic name for .308 in the AR15 configuration?

    More on Chris Kyle. There has been a lot said about the great cost of the wars in Afghanistan and Iraq. However, it seems like there is a group of people–like the SEALs in Kyle’s book–who loved them. They exulted in combat. They hated being away from it. And they were consumed with jealousy about anyone who got more action than them. And this was all while being very fatalistic about getting killed on the battlefield. A strange mindset to be sure. Most of their routine seemed to consist of fighting, working out, and playing video games, but fighting was preferred before everything.

    Victor and BG_Farmer, thanks for your comments about follow through. BG_Farmer, by never failing to miss with a shot that you see hitting the target, you are approaching Vulcan philosophy that there is nothing that is not real. 🙂 Anyway, how true about the urge to snipe instead of working with the wobble. It’s like original sin. I can explain how 6’2″ and 225 pounds can be reduced to complete immobility by a 3 pound trigger. You guys also seemed to have solved another problem without being aware of it which is my Dad’s shooting performance with the pistols. He can’t hit anything at 25 yards (the minimum distance at our range) and is rapidly losing interest. I can’t figure it out. We’ve got him using both front and rear sights, but his shots go all over the place–high, low, left and right. There are no gross errors of technique that I can see. I can sort of understand the misses with the .45 and the other heavy calibers but he’s not connecting with the .22LR either. After hundreds of rounds, his target has almost no mark on it. I think the problem may be follow-through. He is very skeptical and argumentative about this saying that the round has already left the gun by the time he is aware of it. I try to make the analogy with the follow through in tennis where the ball is also on its way after contact, but he’s resisting. I think the thing to do is exhort him further about follow-through and then take him to an indoor range with a 7 yard distance. If you have any ideas about how to describe follow-through that would help. David Tubb says that you try to call your shot. I say keep your eyes on the target as the gun recoils, but that’s met with some resistance. What else can be said?

    Okay, I can’t resist a bit of Tokyo Drift. This refers to a technique in Japanese hot rod racing of skidding your car but there is a deeper ethos of pushing the envelope of possibility with skill and daring. Anyway, what puzzles me is that I thought skidding is something you want to avoid when driving fast. Maybe this technique is conditioned by the tightly compacted courses they drive in Japan which go through parking structures and down twisting mountain roads. The ultimate achievement is hitting a 90 degree turn into a parking ramp at high speed and skidding your way to the top which does look pretty difficult. Anyway, I will confess at getting caught up in this movie series in spite of myself with their hot rods and fast women. In one scene, a guy skids a complete circle around a parked car with two women, and when he comes to a stop, they just hand him a paper with their phone numbers. Or two guys are facing off with teeth clenched and muscles bulging when some little beauty steps up and says, “Why don’t you nice boys let your cars do the talking. Winner gets me.” There is a kind of mounting hilarity to all this. You experienced racers like CowBoyStar Dad and J-F wouldn’t have this in your backgrounds now would you? 🙂

    Matt61

    • Matt,
      Just to be clear, I didn’t mean every shot hits perfectly, just the ones that are executed properly, and I am constantly struggling to up the ratio! Flint is a good master, because even the the “perfect run” can be broken by a dull flint or a soupy pan, etc. Recovering from that sort of thing (and the flinch that often comes along with it) is the real challenge to “faith” and discipline.

      It may be foolish for me to offer an observation about pistol shooting, but I will rush in because I’ve been doing a good bit of it lately, and I’m probably closer to your father’s status than yours. When I started with my .50 cal. ML’er pistol, I couldn’t hit the side of a barn and blamed all sorts of things. What it came down to is the grip and follow-through. Grip has to be absolutely consistent from shot to shot, and, at least with the pistols I shoot, grip and trigger pull/pressure have a huge impact on the point of impact. With a .45, I worry less about the aim than how the grip feels in my hand — by changing pressure points, the POI shifts predictable. The .45 I shoot has a fairly heavy trigger (I actually prefer this for such guns) and my trigger pull works in conjunction with the grip. Dry fire while concentrating on how/where the sights move against a target as you pull the trigger to get an idea about what is going on. Definitely start him at 7 yards — it is frustrating to miss the target at 25 and pointless also, because you cannot see where the shots are going many times, so there is no feedback to work with. I shoot the .50 cal. caplock pistol at 25 yards in a mediocre way, but it took an embarrassingly long time to get to even that point! I know without doubt that I am a really poor pistol shot, but a few times when I shot a .45 at the range at 7 or even 10 yards, some (much more experienced) shooters expressed approval of the groups and bewilderment at my technique (you aren’t the only one who finds single-hand grip unusual) :)! I would suggest getting your father to approach the task as problem to think through, i.e. let him shoot a close target and see what effect HE is having on the point of impact, then try ways to bring it closer to the point of aim. He may be like me in that he simply cannot follow “the rules” without deriving them for himself first :)!

    • PS. I like equating follow-through to aiming. You shouldn’t stop aiming just because you pulled the trigger. This is a real task with something like the .30-06, where you can see the sight picture in the scope jump/distort on recoil or a flintlock where you sometimes see a small explosion in your peripheral vision, but keep aiming and holding on target. Maybe it is overkill, but focusing on aiming (follow-through) prevents dropping or flinching too early which is what causes most shots to go astray.

      One of my recently departed friends was a “natural” — shot perfectly and after a few months of muzzleloader shooting was beating the pants off people with 40 years experience. Then one day something caused him to start flinching, and he was missing targets (not missing X’s, missing the target PAPER). He hadn’t changed a thing otherwise and didn’t know he was doing it, and it made a huge difference (e.g. 90 out of 200 points) — it is that important to follow-through and not stop when you think you have fired the gun.

      • BG_Farmer,

        My buddy, Dave Kimes, told me that when setting a world record in high power rifle, he kept pretending that he was shooting an air-rifle (an FWB 300, in his case) with each shot. He basically conditioned himself this way, and it paid off big time. Again, it was about anticipation, but this time because of the heavy expected recoil. We are normally already prone to anticipation, because we subconsciously think we know when the gun will go off and loose focus within a tiny faction of a second, including between the time the hammer fell and the shot left the barrel.

        Its all so very mental. I guess shooters are especially mental. 🙂

        Victor

    • Drifting isn’t really racing. It’s more like automotive ballet.
      The point is to get as much angle while maintaining as much speed as possible thru a turn without losing control.

      Just search it on youtube and you’ll see it’s quite busy in the car and accident happen often but areusually only cosmetic qnd why the bumpers are often attached using tie wraps so it doesn’t break when making contact with another car or wall.

      The Japanese started it on mountain roads and it started in north america with Japanese rwd cars and people quickly realised that we had already had what was needed here for less money.
      Mustangs and Camaros are now very popular in drifting.

      Most young adults who live in places where there’s snow already do this in empty parking lots and then with a little more speed you can try it on wet pavement and some eventually graduate to dry pavement.

      It’s a lot of fun to watch and do. Search for Ken Block gymkhana for the extreme version of it with a 4wd car which is harder because all 4 wheels have to be spinning for the car drift.

      J-F

    • Matt61,

      I think I know how to help your father with follow-through, although what you’ve told him thus far is sufficient. Months ago J-F asked, how do you check your natural point of aim. I know how I check it, but I decided to ask a friend of mine, who is an Olympic and World champion.

      My friend, Dave Kimes, says that he checks his natural point of aim after each shot by seeing where the gun settles. In other words, say focused until the gun settles. As it turns out, I do the same thing, and have said as much before.

      Again, anticipation of the gun going off will usually lead to flinching, which is in effect sniping. ANYTIME you stop focusing on keeping the sights aligned, ANYTHING can happen.

      So your dad will benefit from BOTH trying to call his shots, AND waiting for the gun to settle back into the place he thought he was aiming, all the time focusing on the sights.

      Now, when you say that he misses the target all of the time, that tells me that he’s having trouble focusing on the sights themselves. That reminds me of a friend who could barely hit the paper, and usually hit low. He was a smart guy, but was stubborn about what he considered to be “common sense”. Within a day, I got him on the black. His problem was that he insisted that he look at the target, while trying to keep his sights aligned. You can’t do both! Your father may be struggling with this little detail.

      This is why you must first find your natural point of aim (NPA). Once you find your NPA, you should be able to stay focused on keeping your front sight centered with the rear (which is fixed at your hand), and the actual bull should remain a blur throughout the shot. Adding a check for NPA at the end of a shot (after everything settles) might further help.

      Again, small deviations in sight alignment project larger at the target than the wobble of your arm and shooting hand. Another thing to check for is timing and breadth control. Make sure that he is not taking too long to get a shot off. Once you’ve established your NPA, you should try to DELIBERATELY get your shot off as soon as you obtain your sight picture (sight alignment in the general area of the target).

      My pistol coach, Stan Hulstrom constantly de-emphasized SIGHT PICTURE and focused almost exclusively on SIGHT ALIGNMENT, because he knew that too much emphasis on sight picture was misleading with respect to what really mattered.

      Good discussion. Thanks!

      Victor

    • Per Wikipedia

      .30M1 110gr at 1990fps yielding 967ft-lbs from 18″ barrel

      .357Mag with a LIGHT bullet (125gr) at 1600fps gives 710ft-lb from a 4″ barrel

      It’s also larger in diameter, so less likely to over penetrate.

      The M1 carbine was meant as sort of a more accurate lightweight gun to be carried instead of the 1911.

      {What is this? Three posts in a rwo where the CAPTCHA answer was “1”}

  9. Drifting a car provides a fun sensation, but drifting completely around a curve does not result in the fastest way around a track. The laws of physics say that cars can travel faster in straight lines than they can turning.

    Putting a car in a drift is to commit it to an arc around the curve. Any attempt to seriously alter that arc can upset the balance of the car. Unload the rear wheels and the car will want to back into the wall.
    Unload the front wheels and it will try to plow into the wall nose first.

    A car in a drift all the way around the turn (like in the movie) will tend to run high, because a wide arc can be taken at higher speed than a tight arc.

    Generally, in a real race, it is better to brake a little early coming into the corner, turn the car as early as possible before the apex of the turn, , and come off the turn full throttle in a straight line down the straightaway while the drifters are still up there turning their cars and hugging the wall.
    Drivers attempting to brake late, carrying more speed into the turn, are apt to lose their temporary advantage by turning late and finding their cars still turning while their competitors zip past in a straight line.

    J-F and Cowboystar Dad understand this very well. I am only posting this in an attempt to explain it to the rest of us.

    I too learned this on snow and ice before practicing it on a dirt track.

    Les

  10. So what is the benefit suppose to be when you replace the main spring with a (as its commonly called; a gas spring or nitro spring).
    I know you are suppose to be able to leave it cocked and not worry about stressing it like you would a spring.

    But are the manufacturers redesigning the internals for the gas springs? And if not are they matched that close in design?

    • GF1,

      You know the benefits already. They are lower weight, less vibration, faster shot time, can remain cocked without damage to the spring, and so on.

      The designers design the gas spring to the existing internals of the gun, not vice-versa. Some are done better than others, as would be expected.

      B.B.

        • Might require two or three variations — since the change in trigger series also changed the lock-up system. The T01 uses a set of three balls (as I recall — when one’s DSL is stuck at 224kbps downlink and 384kbps up, one is reluctant to search the web for the details); the T05 is more of a simple ledge.

          It would also be difficult to convert if a gun used an extension that went through the spring for lockup?

  11. how did the accuracy do when you put the big power kit in? im always under the suspicion that when you hit a certain speed , accuracy tends to drop as the pellet approaches subsonic speed

  12. interesting. I need to smooth out my Diana 350 pro. I put a Chinese long barrel onb it as its almost too much for my old tired arms. I like the power and accuracy but its a rough cocking gun and needs a little taming down as its just way stout. my Diana 54 and 460 are a lot easier for me to use. but in .22 its realy got the power . hits like a standard .22 rf round

  13. hi you make two statements that I don’t agree with
    1 that fitting heavier spring doesn’t have a direct affect on speed of pellet
    2 fitting heavier spring doesn’t increase power without making other changes
    I changed only the spring on hw 35 and the power increased significantly admittedly harsh to fire and lot of preload so not advisable but your statement is wrong also by changing the mainspring I did directly alter the pellet speed In my opinion !

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