So I've been researching recoil spring options for my new G20, and in that research I've found one thing that sticks in my craw: some absolutely absurd explanations for the effects of changing "spring weight" (I'll explain the quotes in a minute).
I'm guessing the overwhelming majority of INGOers already know this, so please pardon my having to vent.
Consider this from "Custom Glock":
You can produce identical spring *rates* with very different weight springs. For a given rate, a coil spring can either have heavier wire and more turns per inch, or thinner wire with the turns farther apart. They will have different fatigue properties and other spring considerations (set height, solid height, etc), but they can be made to have the same *rate* within a range.
Let's also establish up front that the "perfect" recoil spring only exists for a given load. Even with identical charges, going up or down in bullet weight will change the "ideal" spring rate.
So the above statement that a shooter "does more work" with a stiffer recoil spring is absolutely bogus. The shooter will not "do more work" either in a practical sense or in the sense of physics. Unless the spring is so stiff that it won't allow full slide travel (potentially causing FTF), the shooter does the same amount of work. Either the shooter has to resist the reaction force of the spring compression, or he must resist the inertia of the slide once the spring is fully compressed.
The lighter the spring, the less energy it stores, leaving more impact energy to the shooter's hands once the slide is fully retracted. A heavier spring stores more energy, so there is less kinetic energy sent to the shooter's hand when the slide is fully retracted (but marginally more force sent WHILE the spring is compressing).
We can see now why the "more muzzle flip from a heavier spring" is also false. Muzzle flip comes not from the relatively small force to compress the spring, but from the huge impact when the slide fully retracts.
This is plainly visible in this video. When does the muzzle rise the fastest? When the slide smacks the stops:
http://youtu.be/ysp3XHxT9mk
So a heavier spring will not cause more muzzle flip. It will reduce it.
Does it reduce recoil? No. There's still a reaction force-- Newton's law of equal and opposite reaction is a "law" for a reason.
But the perception of recoil can be manipulated to produce a higher *average* recoil force in exchange for a smaller *instantaneous* recoil force. However, the total area under the curve will always be the same.
I'm guessing the overwhelming majority of INGOers already know this, so please pardon my having to vent.
Consider this from "Custom Glock":
Let's begin with an important clarification related to the quotation marks I used in "spring weight." The force a spring exerts is not a function of its "weight", but a function of its RATE.UPDATE:
We just received the new ISMI 11 pound recoil springs. These should eliminate or greatly reduce the need for cutting 13s. I have not done extensive testing yet but they should work great in the 9mm guns and the compacts.
Effects of a lighter spring:
Recoil is transferred to the shooter in a shorter duration of time because the slide is moving at a higher velocity. This is often perceived as less recoil and reduced muzzle flip.
With a lighter spring the shooter also has less force to counteract, or you don’t have to work as hard. This usually reduces muzzle flip.
Less force to counteract reduces the odds of producing a limp wrist style jam.
A lighter spring will result is reduced muzzle dip when the slide closes keeping sights steadier and on target for a faster follow-up shot.
Light springs are particularly helpful to smaller shooters like children, women or anyone else having trouble keeping their wrists locked.
Effects of a Heavier spring:
Recoil is transferred to the shooter over a longer duration of time due to lower slide velocities.
Slower slides equal a longer recovery time for the shooter.
The shooter does more work, as there is more force to counteract. This often causes and increase in muzzle flip.
The chances of a limp wrist style jam are increased, as there is more force working to unlock your wrists.
The chance of the slide short stroking and causing a feed jam is increased.
Increased muzzle dip when the slide closes for a slower follow-up shot.
You can produce identical spring *rates* with very different weight springs. For a given rate, a coil spring can either have heavier wire and more turns per inch, or thinner wire with the turns farther apart. They will have different fatigue properties and other spring considerations (set height, solid height, etc), but they can be made to have the same *rate* within a range.
Let's also establish up front that the "perfect" recoil spring only exists for a given load. Even with identical charges, going up or down in bullet weight will change the "ideal" spring rate.
So the above statement that a shooter "does more work" with a stiffer recoil spring is absolutely bogus. The shooter will not "do more work" either in a practical sense or in the sense of physics. Unless the spring is so stiff that it won't allow full slide travel (potentially causing FTF), the shooter does the same amount of work. Either the shooter has to resist the reaction force of the spring compression, or he must resist the inertia of the slide once the spring is fully compressed.
The lighter the spring, the less energy it stores, leaving more impact energy to the shooter's hands once the slide is fully retracted. A heavier spring stores more energy, so there is less kinetic energy sent to the shooter's hand when the slide is fully retracted (but marginally more force sent WHILE the spring is compressing).
We can see now why the "more muzzle flip from a heavier spring" is also false. Muzzle flip comes not from the relatively small force to compress the spring, but from the huge impact when the slide fully retracts.
This is plainly visible in this video. When does the muzzle rise the fastest? When the slide smacks the stops:
http://youtu.be/ysp3XHxT9mk
So a heavier spring will not cause more muzzle flip. It will reduce it.
Does it reduce recoil? No. There's still a reaction force-- Newton's law of equal and opposite reaction is a "law" for a reason.
But the perception of recoil can be manipulated to produce a higher *average* recoil force in exchange for a smaller *instantaneous* recoil force. However, the total area under the curve will always be the same.
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