Took my Ruger 1911 to the range today and it is so hard to rack. I have a number of 1911's but none this difficult. When I got home I tried a Colt recoil spring, but not much difference even though the Colt was quite a bit shorter than the Ruger. Is this a Hammer spring issue?
What have other done?
First, the length of the spring is only a small part of it. The number of coils and the wire diameter are much more important in determining the spring's strength and rate.
You need to determine what is causing the slide to be difficult to hand cycle by process of elimination.
Field strip it and install the slide without the barrel and spring. Cock the hammer and cycle it. Then, lower the hammer and cycle it again to see if there's a marked difference. The hammer will make it a little tight at first, then "break" much like a compound bow when it starts cocking.
If it's much easier without the recoil spring, but with the hammer down, the slide is oversprung and you need a softer spring. Browning's original was around 14.5 pounds, not...as many believe...16.
Likewise, a small radius on the firing pin stop will cause the slide to be a bit tight when it starts. I doubt that Ruger has used an overly heavy mainspring, but I haven't examined one, so it's possible.
If, after eliminating both springs you still have a hard slide, about the only thing left to suspect is the disconnect dragging hard on the center or cocking rail.
To test for that, Pull the trigger and hold it firmly rearward. Hand cycle the slide while holding the trigger...then do it again. If it eases up on the second try, the disconnect is dragging. If it is, you'll need to determine whether the cause is an out of spec disconnect standing too high above the frame, or excessive sear spring loading on the center leg....or possibly both.
There's also a small chance that the hammer is dragging hard on the center rail. Check by seeing if the hammer will overcock slightly past full cock with the slide about halfway back. If it will, that's not the problem.
You can reduce the effort quite a bit by simply cocking the hammer first.