We know that the mainspring must push the hammer with sufficient force to strike the primer with the firing pin to reliably ignite the primer.
How would you characterize the difference between a heavier rate spring and a shorter strain screw versus a lighter rate spring and a longer strain screw?
Grant Cunningham pointed out one important difference: the arch of the spring will be different and may interfere with the grip screw.
If a flat spring has a linear rate and we add some amount of preload with the strain screw, the spring will start compressing beyond the strain screw's preload along that line of rate in pounds per inch.
If another flat spring has a lower linear rate than the first, we will need to add more preload with the strain screw to achieve the minimum amount of force for reliable ignition (all other things being equal). Although the cocking motion will begin to compress the mainspring at a point farther along its line of rate because of the greater preload, the force to fully compress it (to the point where the sear releases) will increase less over the same distance as the higher rate spring. The peak force or the area under the force/distance line will not necessarily be less, but the force will increase less over the distance.
Why might it be more desirable to achieve reliable ignition one way or the other?
How would you characterize the difference between a heavier rate spring and a shorter strain screw versus a lighter rate spring and a longer strain screw?
Grant Cunningham pointed out one important difference: the arch of the spring will be different and may interfere with the grip screw.
If a flat spring has a linear rate and we add some amount of preload with the strain screw, the spring will start compressing beyond the strain screw's preload along that line of rate in pounds per inch.
If another flat spring has a lower linear rate than the first, we will need to add more preload with the strain screw to achieve the minimum amount of force for reliable ignition (all other things being equal). Although the cocking motion will begin to compress the mainspring at a point farther along its line of rate because of the greater preload, the force to fully compress it (to the point where the sear releases) will increase less over the same distance as the higher rate spring. The peak force or the area under the force/distance line will not necessarily be less, but the force will increase less over the distance.
Why might it be more desirable to achieve reliable ignition one way or the other?