That`s what they say but Nitro says they`ve put thousands of rounds through Kick`s tubes and Never had a problem. If you hear me crying next week it`s because my Kicks couldn`t take the Hevi-shot loads I`m going to try this weekend. I would like to know why Kick`s doesn`t think their tubes are strong enough for Hevi-shot? Are they using cheaper quality steel then others? The restrictions are the same so maybe I`d better switch to Rhino and get a choke that can be used with everything. I just got off the phone with Kicks and they say there is NO CHOKE TUBE that can shoot Hevi-shot not Kicks ,Rhino Remington none. Their take is Hevi-shot is harder than the hardest Choke so barrel damage will result from using Hevi-shot in any gun.