You can get a surplusmilitary chamber brush or equivalent, cheaply, just about anywhere. Works great, last long time. Here are just a few places you can get them.

http://www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=1234&title=M16+%26+AR-15+CHAMBER+BRUSHES

http://www.m-aparts.com/productsDetail.asp?id=1184

http://www.model1sales.com/search-results.cfm

http://www.sogarmory.com/Products.aspx?srch=chamber+brush&x=5&y=20

http://www.dxcart.com/cart/search.mhtml