I know this thread is old, but this task wasn't high on the todo list when I last posted in it. But its getting that time a year again.
I ordered this part on one of those days when Brownells had FREE shipping with no minimum order
I got the original spring out and decided to compare the compression of each. The new spring in actually a little less (3-5oz) pressure for the same distance (measure on a weighting scale compressing both to the same height). But the way the new spring is shaped (formed) it applies much more of it's force to the rear of the follower. And that is where I WAS having the issue as the bolt was occasionally passing over the case head because it was squatting a little.
I did have to trim a little off the new spring to "fit it" to the follower.
Ran about 6 magazines full through it, no issues, works better than it ever has since I had it.
Be Safe,
