This is why mags have a release button that is pressed ussually by the hop up when you slap the mag in, so that the hop up gets a full dose of BB's.
In other words the only damaging affect of reloading is that you loose a couple BB's that were in the feeder tube. If you are having a miss feed, check your mags that when loaded the spring loaded catch still works. After that check to make sure that the AEG itself is engadging that release. If its not, then you have a problem. But you shouldn't have that problem in difference between a full or half empty mag.
"The hydrogen economy car from the people who brought you the 'Hindenburg
'" - Glen Foster
Condoms do not guarantee safe sex any more. A friend of mine wore one and was shot by the woman's husband!