The first factory mag I had I cleaned about every other time I cleaned my rifle, after about 3,000 rounds it stoped feeding. The next one I got I cleaned every time I cleaned the rifle and that one lasted about 4,000 rounds. I have a friend who had a similar problem but I would be suprised if he ever cleaned his magazine. Now I use a butler creek 10 rd mag and have yet to have a feeding problem in the over 15,000 rounds I have put through it. Its possible I just got unlucky with the factory mags and very lucky with the after market ones.