B.
To me it sounds like the bottle you are using might be wrong. I have a 3 month old who started out on NUK nipples as I had used them for my other two children but they flowed too fast for her and she did the same thing gulpped and slirpped and cried and its because she was getting too much air. Plus you said that he got some running down his chin, so maybe hes not really getting 4 oz, maybe hes getting 3.5! My oldest daughter had GERD and she was a spitter upper, and I mean projectile! Thats a very common symptom. In the end my 3 month old like the playtex ORIGINAL nipples, the kind that use the plastic liners. the nipple is latex not clear silacone. it is a soft nipple and my daughter was able to latch on tightly and avoid excess gulping of air. Also you can push the air out of the liner to decrease the amount of air he gets. If you buy the paytex bottles they come with a set of liners and the correct nipple. this will allow you to try to see if it works, and if it doesnt its worth tring several different styles to rule that part out before buying expensive formula or paying for an unnecessary dr. visit.
I hope this helps!
B.