Welcome aboard!! This is a great site with some great guys who are very knowledgeable about these rifles. Congratulations on your gift from your Grandfather. I bet he had some great stories about the rifle. Thanks for shring the picture. Ask your questions and be prepared for some straight forward answers.
From what I can see a fine looking 81 and a great caliber to get you started - the one that the rifles were designed for. I've found the ammo at gun shows for "relatively" reasonable prices.
Welcome aboard. Now for your next one there are some good buys on GB!
Though defensive violence will always be “a sad necessity” in the eyes of men of principle, it would be still more unfortunate if wrongdoers should dominate just men. - St. Augustine