I took out my brand new 10/22 sporter and a BC steel lips mag this past weekend. I was limited on time so I only put 4 mags full (of the BCmag) down the tube. 25 each of Federal Champion, Win 555, Win Xpert HV, Blazer. Only one issue with the very first round of Win Xpert. Other then that mag performed flawlessly. The factory mag was 40 for 40. No problems.