When you are at the Prancing Pony Inn and have just defeated the two ruffians who stole your dagger, go through the open window and climb up the ladder. Once up, you should notice that the ring is spinning in its slot. Turn to the right and use the ring. You should see a platform with both an elven and dwarven shot. Collect them and jump back to the ladder platform. Then, take off the ring and put it back on. You will notice that the items appear again. Do this as many times as needed to get unlimited elven and dwarven shots.