Check the width of the magazines. Adjust your calipers jaws to just gently kiss the sides of the magazines when you move them through. Compare that measurement to working magazines. I think you may find that dropping has gradually sprung them a little. You may have to pull the followers and springs and use soft jaws on a vice to squeeze them back to original form.
Gunsite Orange Hat Family Member
CMP Certified GSM Master Instructor
NRA Certified Rifle Instructor
NRA Patron Member