Cadex CDX-R7 SPTR Series Short Action Hybrid Tan/BlackNot everyone is a firm believer in carbon fiber barrels. Some people are more conservative and they prefer a traditional stainless steel barrel. For this reason we designed the CDX R7 SPTR, a variant equipped with a sporter profiled stainless barrel. We added some longitudinal flutes for weight reduction, faster cooling and nicer look. The CDX R7 SPTR shares the same features as the CDX R7 CRBN except the barrel type, which makes it more affordable.