Tom Libby is shooting a Kensler rail, and it really shoots well. If you ever come to an unlimited match in Tacoma, Wa. there's quite a few tensioned barrels that are cooled but I am pretty sure its not water! I asked once and I thought they told me that oil was used, could be wrong but thats my story and I am sticking to it. Most if not all of them were made and installed by Craig Kensler,as I recall. Last year Larry White was also playing around with a tensioned barrel,Interesting concept but as I recollect they seem to still get beat by guys just shooting normal rails.