I would stretch the spring first. It wont hurt anything, and will help keep more upward pressure on the rounds to better judge what kind of a differance tweaking the feed lips is making. 1911's like upward pressure on the rounds, as long as its not so much that it drastically increased the friction of the round leaving the mag, which 3-5 inches will not effect.
If these are used mags, then there is a good chance they were kept loaded, and just stretching the spring will be the cure all anyways.
I always stretch the springs on EVERY used mag of unknown history that i buy. I doesnt hurt, and its just common sense to start from a known point.
No one has mentioned this so I am putting on my flame suit.
I don't like CM shooting star mags for Kimber or any other aluminum framed 1911.
The follower on these mags will move forward enough on the last round to contact the aluminum feed ramp part of your frame.
Over the course of time it will chew up the feed ramp.
If you take your empty mag and push the follower outward, you will see what I mean.
Original Colt Officers mags have a tapered follower that will not move forward past the end of the magazine, even on the last round.
Wilson magazines have a redesigned follower that can't go past the front of the mag body.
I use Wilsons for my Kimber Compact
Or if you want the best magazine on the market today (IMHO of course) get a Tripp Cobra mag with the hybrid follower.
I pulled the mags apart and the top of the spting was flat. I bent it up and problem looks to be solved. I think I am going to order some more springs for these mags.
And yet i have still not recieved any rep
/Flamesuit on!
I don't think it's ever a good idea to stretch a spring. A poorly designed/made/material spring will take a set and it's overall length becomes less. What you are supposed to do is add preload at the bottom. When you stretch a spring like that you are going past it's designed elastic limit point and it can cause breakage. It won't heal itself after that ever. If it's been stretched then get rid of it. A good spring life expectancy should be thousands of cycles & last tens of years even fully compressed.