Mike is still making bore guides......Thank goodness!Lucas makes fine cartridges/caliber specific. Last time I messaged him I thought he had told me he had health issues and was no longer doing it….maybe I am misremembering though….it was a a year or so back. PMA make a good one as well. Haven't used 21st Century but if they do make them I'd assume they are top notch as well. Mine are Lucas and PMA