Interesting review. I have a Ciener and it has worked without problems in my Bushmaster upper. No feed problems even with Remington bulk, save the numerous no fires.
The Black Dog mags are superb, they deserve some type of award for their products. I need to get more.
The mags are a trial to load to the advertised 27 but I have loaded both mags to their full capacity and they work flawlessly. I do have a mag loader coming from Midway, and a bad case of "Mag Thumb".
One Qualification, use plated ammo!