Just where exactly does it say this data is not to be used in gain twist barrels? Why produce data that is only safe to use in just one of a dozen or so firearm variants chambered for the same cartridge then neglect to include this information in the hand written warnings at the bottom of the sheet? To date I've put 200 or so rounds loaded using this data through an M1938 short rifle w/gain twist and without a single issue of any kind.