That is a perfect size
To wind your own... Buy a 1/2 pound of music wire and spin one up on lathe ..
Diameter of Music wire has the biggest effect on spring rate.
Its a simple coil spring, no heat treat required, should take less than 30 minutes and .25 cents worth of spring wire.
Backgear slowest speed. Rig a friction pad/clamp in toolholder to add a fair amount of tension to music wire. I hand spin chuck to get tension adjusted.
3 inches long should be fine (remember more length/weight will add to lock time...) DO NOT GET TANGLED IN SPRING WIRE (I cut into lengths only long enough for the job)
For a Super 700 style, just copy pitch of the 700 spring, add about 25% to allow for first compression settling, and wind on a approx .250 diameter mandrel (the spring will expand to around 5/16 or larger after tension is removed). Adjust ID by mandrel diameter after a few short practice pieces. (I start large and turn mandrel down to get where it needs to be)
For coarse pitch 1911 pistol style recoil springs, I just freehand carriage to get pitch...
Mandrel is simple scrap piece of rod with a 1/16 or so hole cross drilled in near chuck side to hold music wire (with a couple wraps around mandrel), and a center hole for tailstock. After you get dia of mandrel right, you can do a couple close winds near cross hole, engage half nuts at what ever pitch is closest. Disengage at opposite end of spring and do a few close winds to finish.
I cut wire going through mandrel free with a Dremal Cut off wheel and slide off to tailstock side of mandrel... flatten ends of springs by grinding and have fun...