Airsoft JG Steyr AUG Military keeps jamming!?!?

The problem is probably because your gun is new. If it misfeeds like the first day you got it, you have to let it "break in." After you've put around 2-4 magazines-full worth of bb's and it still keeps misfeeding, most likely your magazine is a defect. Buy a new AUG magazine. Oh BTW .25's aren't too heavy, I use those for my Echo1 M16 Stag Arms DMR, Don't listen to the other guy. In fact, the max for an AEG should be around .28, Over .30 should be used in airsoft sniper rifles.