There's a rectangularly shaped tab (for lack of a better word) on the back of those magazines that retracts when depressing the follower. Are you able to push that tab into the mag without touching the follower, or is it locked in place until you depress the follower. I think I might have some defective ones and I'm just trying to troubleshoot. FWI...the tabs on the Magpuls for 3+ retract without depressing the follower, but not so with my factory mags.
Thanks for any help on this.