If it's new it should have included a manual that will tell you what kind of projectiles and powder you can use in it. If it isn't new it wouldn't hurt to write Remington and request a copy of the manual.
I'd be extremely surprised if they recommend against using the pellets, though. A different question to ask is whether or not your game laws allow the use of pellets. Here in Colorado they do not.
There are still some who insist a scope is not needed for the type hunting they do, ignoring the advances of the last 150 years in optical sights. (Even the ultra-conservative US Army has adopted optical sights.) The idea that in some special circumstances open iron sights or aperture (peep) sights might be more useful is not lost on me, but with the inevitable advance of age comes the reduction in visual acuity needed for using iron sights.
I believe that many who completely resist the idea of...