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.
Here is an inexpenive and effective deer feeder I made recently.
No batteries to go dead, no hoisting it up in the tree, plenty of capacity, very easy to fill - so far, I love it.
I have made two of these and they are easy to build.
An empty 55 gallon drum, some 2x4's, some PVC tubing and fittings, a little bit of hardware and some paint - and you are ready to go.
I designed it so you can stand on the lower rung and fill it - the top is about 6.5 feet above the ground.
It holds about 375...