The BBTI data suggest that the .327 fed mag from a 16" barrel is approaching 300blackout from a short barrel. 100gr bullet at 2150fps for the .327 Fed, where 300black with a 110gr TTSX is around 2000fps in a shorter barrel.
And at 16" I think the 300blk is only a 100 or so FPS faster.
It sure seems to me like the 327 fed in a lever gun is sort of an Old West spin on a modern 300blk carbine.
That's a pretty fair comparison. Where the .300 BO pulls significantly ahead is with ability to use the wide variety of available .308 bullets. The .327 is far more limited in bullet selection and even worse, IMO, most of them were designed for .32 H&R maximum velocities.