I previously wrote a review that said unusable - ProMag Beretta 21A Bobcat 7 Round Pistol Magazine

Taking some advice, I cleaned the magazine, reverse to retaining screw to match the beretta magazine (don't know why that would help, but couldn't hurt). CLP oil is not lubricating enough to help this magazine fit into the 21A beretta but TW25B lubricant (synthetic grease) that I use on my AR bolt worked. I slathered the exterior of the Pro Mag magazine and it slides so easily all the way in and out now that just pushing the eject button and the magazine pops out all on its own. So I'll move my stars from1 to 3. If it fit like this from the getgo, I'd have given it 5 stars.