All I have is the factory magazine and the current Aguila has been working fine in my rifle and magazine. Can you measure the case head diameter for the ammunition you have that is discrepant? I'll do the same when I get home from work tonight and post the dimensionI suspect the Aguila 5mm ammo that I have has dimensional problems with rim diameter. The diameter of the rim seems a bit too large. I cannot get it to load in 4 magazines that I have. They are after market magazines, but two different manufacturers. Anyone else experiencing this problem?