Consistent fail to feed - FAB Defense 4 Round Magazine extension for Glock 43

I wanted to expand the capacity of my G43, so I thought these were a good option. They installed easy enough to my factory mags, but they look Frankensteinish. Not that looks make the gun, but these are WAY to long and very fugly. Also, good luck getting all 4 extra rounds in. You can probably cram the fourth one in, but to what harm of the mag extension. I didn't want to find out. Then on to the range. Well, these mag extensions had consistent fail to feed issues on the last round. I don't shoot junk ammo, Federal Premium HST, but more times than not, the last round would not feed. These are now in my ammo locker waiting for a new home. Maybe I'll use them to practice my stippling, that's about all they're good for. Look elswhere if you plan to use these for self defense.