I had an opportunity to empty my BC mags yesterday afternoon and they worked flawlessly 25 rounds in each using the loader! This afternoon, I sat down with the BC mags, some precision measuring tools and compared the BC mags with my two TI The mags that have frustrated me so badly. I can see several important differences. The plastic follower which pushes the rounds up for chambering is much lower with a different angle on the BCs. Also the steel pin at the rear of the BC mags are larger and more substantial than that on the TIs. I will keep trying to get the TI to work and report any solution. However, I am enthusiastic for the BCs which were cheaper than the black adjustable TIs. Possibly the TI mag being adjustable with the four screws was where I went wrong when I tried to follow the instructions. The BC mag is looser but is no problem and two mags may he snapped together, like a 69.