RE: Elk Hunting With A Slug Gun?????
A 438 grain, 45 caliber, Barnes X bullet at 1500 fps I would think would do quite nicely.
If I were going after elk with a slug my first choice would be a Winchester 3", 385 grainpartition gold or the Winchester 3"XP3 slug.
Assuming they were accurate but both are starting out at aproximately 2000 fps. and are true 45-70 performance from a shotgun.