Need some advice..

Normally projectile vomiting after a feed is usually due to overfeeding and newborns in particular doesn't have a matured stomach and a week esophagus which is responsible for keeping the milk down, just keep in mind that his stomach is a size of an egg. What you can do is keep is feed small and have breaks in between to burp him then continue. The grunting is normal, it will decrease when baby gets older. Hang in there! It will pass