That shouldn't be any problem - they are designed to do that and anecdotal reports abound of loaded magazines from WWII era found loaded and still functioning just fine.

I keep nearly a dozen mags loaded for my 1911 government models that I shoot every week at the range and have been doing so for years. I've replaced a spring on only one over the years.

I took a friend to the range last week to shoot his 25 ACP. This gun had been in his drawer for 15 to 20 years whithout being fired. It did not want to feed at first so I cleaned the mag well and after that no FTF. So I would say the spring was not the problem but the accumulation of dust and old oil. I would keep the mag free of oil and solvent and take it out every now and again and pull the ammo and inspect and clean the mag.

Thanks guys. I will keep them fully loaded.

I keep several loaded at one time for my G-21. You just never know when it will hit the fan!!
Scott

if you are really worried about it get some extra magazines and rotate them every 6 months. I do.