Useful read from Wolff's site:
1. What is the difference between conventional and variable recoil springs?
The difference is both physical and operational. On a conventional spring, all the coils are spaced equally apart, except for the closed ends. In a variable recoil spring the space varies between coils with less space between coils at one end and more space between coils at the other end. The way the springs store energy is also different. For example if a conventional recoil spring is compressed 1/2", it might store 1 pound of energy. For every additional 1/2" this spring is compressed it would then store 1 additional pound of energy. When a variable recoil spring is compressed 1/2", it might store 1/4 pound of energy. The next half inch of compression might store 1/2 pound, the next half inch might store 3/4 pound and so on. In other words, a conventional spring stores energy on a straight line and a variable spring stores energy on a curve. If both springs are rated at 16 pounds, they will both store 16 pounds when compressed to the same working length, but the way they get to 16 pounds is different.
2. Should I use a conventional or variable spring when both are available?
The choice is often very subjective. Variable recoil springs reduce the battery load values with increasingly greater recoil load values. This results in easier unlocking, improved recoil energy storage, dampening, feeding, breaching and lockup. Variable recoil springs are particularly beneficial with compensated pistols and when using light target loads where less recoil energy is available. Conventional recoil springs are particularly beneficial when shooting heavier loads where keeping the slide closed as long as possible is desired. The "correct type" of recoil spring is best determined through experimentation and your own personal preference.
3. How heavy should my recoil spring be? What weight recoil spring should I use with a particular load?
These are two very hard questions to answer in exact terms and in most cases an exact answer is not possible. There are many factors which influence the correct weight recoil spring to use. These factors include the particular ammunition brand and load, individual pistol characteristics, individual shooting styles and your individual, subjective feeling of how the gun shoots and should feel. In general terms, the heaviest recoil spring that will allow the pistol to function reliably is the best choice - tempered by the above factors. If your casings are hitting the ground in the 3 to 6 foot range, then the recoil spring is approximately correct. If you are ejecting beyond the 6-8 foot range, then a heavier recoil spring is generally required. If your casings are ejecting less than 3 feet a lighter recoil spring may be needed to assure proper functioning. Taking these factors into consideration, it then comes down to how the gun feels and performs when shooting - in your judgment. Using too light a recoil spring can result in damage to the pistol and possible injury to you.
4. How often should I change my springs?
Wolff Gunsprings are made with the highest grade materials and workmanship. Most Wolff [recoil] springs will remain stable for many thousands of rounds. The performance of your gun is the best indicator of when a spring needs to be replaced. Factors such as increasing ejection distance, improper ejection and/or breaching, lighter hammer indents on primers, misfires, poor cartridge feeding from magazines, frequent jams, stove pipes and other malfunctions are all possible indications of fatigued springs or improper springs. Springs that are subject to higher stress applications such as magazine springs, striker springs and recoil springs will require more frequent replacement than other less stressed springs. Most Wolff recoil springs should be capable of 3000-5000 rounds minimum before changing is required. Some recoil springs in compact pistols, especially where dual springs are replaced by a single spring may require changing after 750 - 1500 rounds. Changes in your firearm's performance are one of the best indicators that a change is needed.
1. What is the difference between conventional and variable recoil springs?
The difference is both physical and operational. On a conventional spring, all the coils are spaced equally apart, except for the closed ends. In a variable recoil spring the space varies between coils with less space between coils at one end and more space between coils at the other end. The way the springs store energy is also different. For example if a conventional recoil spring is compressed 1/2", it might store 1 pound of energy. For every additional 1/2" this spring is compressed it would then store 1 additional pound of energy. When a variable recoil spring is compressed 1/2", it might store 1/4 pound of energy. The next half inch of compression might store 1/2 pound, the next half inch might store 3/4 pound and so on. In other words, a conventional spring stores energy on a straight line and a variable spring stores energy on a curve. If both springs are rated at 16 pounds, they will both store 16 pounds when compressed to the same working length, but the way they get to 16 pounds is different.
2. Should I use a conventional or variable spring when both are available?
The choice is often very subjective. Variable recoil springs reduce the battery load values with increasingly greater recoil load values. This results in easier unlocking, improved recoil energy storage, dampening, feeding, breaching and lockup. Variable recoil springs are particularly beneficial with compensated pistols and when using light target loads where less recoil energy is available. Conventional recoil springs are particularly beneficial when shooting heavier loads where keeping the slide closed as long as possible is desired. The "correct type" of recoil spring is best determined through experimentation and your own personal preference.
3. How heavy should my recoil spring be? What weight recoil spring should I use with a particular load?
These are two very hard questions to answer in exact terms and in most cases an exact answer is not possible. There are many factors which influence the correct weight recoil spring to use. These factors include the particular ammunition brand and load, individual pistol characteristics, individual shooting styles and your individual, subjective feeling of how the gun shoots and should feel. In general terms, the heaviest recoil spring that will allow the pistol to function reliably is the best choice - tempered by the above factors. If your casings are hitting the ground in the 3 to 6 foot range, then the recoil spring is approximately correct. If you are ejecting beyond the 6-8 foot range, then a heavier recoil spring is generally required. If your casings are ejecting less than 3 feet a lighter recoil spring may be needed to assure proper functioning. Taking these factors into consideration, it then comes down to how the gun feels and performs when shooting - in your judgment. Using too light a recoil spring can result in damage to the pistol and possible injury to you.
4. How often should I change my springs?
Wolff Gunsprings are made with the highest grade materials and workmanship. Most Wolff [recoil] springs will remain stable for many thousands of rounds. The performance of your gun is the best indicator of when a spring needs to be replaced. Factors such as increasing ejection distance, improper ejection and/or breaching, lighter hammer indents on primers, misfires, poor cartridge feeding from magazines, frequent jams, stove pipes and other malfunctions are all possible indications of fatigued springs or improper springs. Springs that are subject to higher stress applications such as magazine springs, striker springs and recoil springs will require more frequent replacement than other less stressed springs. Most Wolff recoil springs should be capable of 3000-5000 rounds minimum before changing is required. Some recoil springs in compact pistols, especially where dual springs are replaced by a single spring may require changing after 750 - 1500 rounds. Changes in your firearm's performance are one of the best indicators that a change is needed.

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