[Unclenick]

Well, the problem with recoil tables is they are in energy, which is proportional to what the shooter feels. When you are looking at the mechanics of gun operation, you are interested in momentum. The momentum imparted to the slide and barrel while they are still locked together will be equal and opposite in direction to that of the bullet plus that from the muzzle blast impulse (rocket effect) when the bullet exits.

Rocket effect can be half or more of the total recoil in some overbore rifles. If you ever wondered why muzzle brakes that simply blow outward in all directions accomplish anything, it because they relieve pressure before the bullet uncorks the muzzle, thus reducing rocket effect. They do nothing to reduce recoil from accelerating the bullet unless they are directed rearward, as the arc of a clamshell brake does. Rocket effect is a lower percentage of total recoil in pistols, but is still quite noticeable and depends on powder choice. It is greater with slower powders whose larger charges have more mass to eject, and do so at higher muzzle pressure.

The slide and barrel's combined mass being greater than that of the bullet and propellant is mainly what is responsible for determining their initial rearward velocity in reaction to bullet acceleration and rocket effect. The recoil spring then decelerates it over the distance to the frame, transferring a portion of that momentum to the frame and shooter, with the rest occurring at the point the slide impacts the frame.

So, changing springs will change the percentage of slide momentum that transfers to the shooter before the slide and frame impact. That's it. As long as a spring still has the powder to strip a fresh round from the magazine and feed it, you will have function, even if you change power factor. You will just have more frame battering.

QuickLOAD calculates rocket effect in energy, from which, if you know your slide and barrel mass and travel distance during bullet barrel time, you can work out the momentum. Then, knowing the spring's average force over the distance the slide travels back to meet the frame, you can work out how much it transfers to the frame by decelerating the slide before impact and what more force you need to keep the impact either constant or proportional. The barrel's momentum will transfer through its link, so the shape and type (pivot or slot) will determine that transfer function after the slide and barrel unlock. That part has little to do with feed function, though.

Frankly, you don't want the spring so stiff it mashes cartridges. Once you have a maximum spring that functions without mashing and that doesn't make racking the slide too awkward, if you are then trying to further reduce slide impact, a buffer system is a better way to go than further stiffening the spring. Sprinco has a good one.