Well Marshals articles indicate the really heavy slugs aren't stablized by the 1:38 twist. It would seem I have a 1:38 twist and was thinking of rebarreling. I know Marlin uses 1:20 in some of their guns and it seems to work ok. I have also heard that the faster twist reduces velocity. How much velocity am I going to loose at say 1:25 or 1:18? Just how much twist is needed for the 350+ weight slugs?