Hoppe's 5.56mm/.223cal AR Rifle Brush Multi-Pack (Chamber Brush, Chamber Mop, Bore Brush) 100 percent cotton chamber mop Phosphor bronze brush Stainless steel chamber cleaning Chamber brush, bore brush and chamber mop Standard American 8-32 thread AR Style 5.56mm (.223 cal.) Multi-Pack Chamber Brush, Bore Brush and Chamber Mop 100% cotton chamber mop Double diameter phosphor bronze and stainless steel chamber cleaning brush Phosphor bronze bore brush Standard American 8-32 thread