Picked up a new 450 Bushmaster Gunsite Scout and was hoping to find something else besides the Hornady ammo. I read about a Remington Hog Hammer with a 275 grain barnes bullet but apparently that never actually got produced.

Yep, Hornady 250gr. and Rem. 260gr. Accutip seem to be it for 450 Bushmaster. 458 SOCOM has tons of available loads.

The cheap Ruger Americans should inject some vitality into this caliber. We'll probably see more options by the end of the year.

You got to get into reloading to make 450 Bushmaster shine.  The only factory ammo is Remington with is 260gr Accutip and the two offerings from Hornady both using and 250gr FTX bullet.  Not sure if the Remington Hog Hammer will actually materialize, but have some of the Barnes 275gr TSX bullet ready to reload if I can get some range time to test it.  I have been reloading every thing from 200 gr to 405 gr in my 450 Bushmaster.  I am looking forward to hunting deer with it this year.