A couple months ago I mentioned a had a problem with two new magazines dropping out of my STI. Today I finally got around to fixing it.
I had measured the magazines and found they were 0.020″ narrower than the magazines that worked. It had to be the magazine release. So I bought a new magazine release (on the left below) and compared it to the old one (on the right).
Near the top of the picture compare the width of the material for the little “ledge”. The old one is much narrower. That is what engages the magazine. The old one is worn enough that it does not fully engage the magazine.
I replaced the release, took the gun and magazines to the range and put a couple hundred rounds through the gun without any problems other than one of my old magazines failing to lock the slide back on the last round. Yeah, I know the magazine followers are worn out. I’ll order some new ones and replace them soon. But that is a minor problem compared to the magazines falling out on the first shot.
I’ll do more field testing at the steel match tomorrow but I fully expect the magazine drop problem is fixed now.