I've used it in my 223 and mostly my 8x57. It shoots fantastic in my Sauer 8x57. As to the copper fouling reduction I honestly can't tell on way or another because that particular gun rarely fouls much with any powder. I've speculated that it could be the German steel. I think the additives that powder companies use can work and do but I think it largely depends on the quality of the steel in your barrel and how the copper reducers react with the steel.
