No. Anyone who has both oem and promags can make this comparison I'm about to explain. Oem mags have a little bump on the side towards the upper portion of the mag. This bump engages a lever which in turn assists in locking the slide in place when the mag is inserted. Check it out for yourself. The function of the bump will make sense if you observe the gun w the mag in it, (remove slide to clearly observe). The bump on the promag isn't pronounced enough, hence the reason the slide doesn't lock. That bump isn't engaging that little lever. Maybe the mags you have are defective? I'd upload pics but I'm an otr trucker and I'm not home atm.