Hornady has some oddities and inconsistencies when it comes to max velocities. Latest Hornady manual I have is the older 7th Edition but for 6.5x55 loads the only test rifle is a 1896 military mauser with a 29" barrel. ?!?!? Really? Same book gives 3 different max loads for the 45-70 depending on trap door, Marlin lever or Ruger #1. That puts the old "never can tell what rifle that there hot load might end up in" argument in the shade. .270 Weatherby Mag 26" barrel 130 grain Interlock, SST or Interbond gets over 3200 but less than 3300 due to their weird way of blocking velocities. So just over 3200 fps with a 130gr Interlock & SST with a 26" barrel when the Interlock is supposedly one of the faster bullets to load? That ain't much over what some folks get with the .270 Gay when you're talking 26" barrel. Other examples there if you search. Personally don't have any confidence in how Hornady comes up with some of their data.
Hornady No 10 still has info for the 29 inch barrel and states it will be 200fps or so faster than most sporter barrels. The Barnes manual uses a 24 inch barrel.
