Interesting, but dont see how its very different than a variable weight recoil spring and they dont cost 200 bucks.
https://www.gunsprings.com/index.php?page=FAQ#question1The difference is both physical and operational. With 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 two 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.
