Failure to stay in the handgun - Mec-Gar Glock 17, 9mm Luger, 18 Round Flush Fit Pistol Magazine

I purchased 4 of these here with optics planet. All designed for glock 17 with the added round capacity making it 18 round mags. They arrived in a timely manner, and look great! However, at the range during handgun qualifications (sheriffs deputy) all four mags would fall out the handgun after firing a shot. I even tried with only 2 or 3 rounds loaded in them and still they would eject after firing. I was kicked off the range, then later was allowed to retry. I ran my 3 factory glock 17 mags and had no issues. I can not recommend this product from my experience. I also emailed mec gar but have not had a response from them, been 2 weeks.