Time to knock up a smooth bore barrel for the crosman 600 users.. Easy swap
To be honest I don't think a smooth bore will make a difference. The act doesn't exclude them, it outlaws the action which doesn't specifically exclude a type of barrel.
You can spend thousands and still miss a barn door or spend just enough and enjoy yourself. If you haven't got the talent to start with a million pound won't fix it. Whippet, Russell, a few bang sticks and a flat cap. http://www.smart-tech1st.co.uk