Bringing up milk when burped or at other, sometimes inconvenient times, during the day and night is totally normal for babies. Usually when your baby starts vomiting waterfalls of projectile vomit you assume the worst; "Ohh no! My baby has reflux!"
UPDATE: My little girl is now 6 months old and the vomit and spit up has almost completely stopped.
You do however get some babies, we call them "Happy Spitters" who just by nature bring up more milk than others. My little girl is one of those Happy Spitters.
If your baby is not in pain or discomfort while having these projectile vomits, it means that the stomach acid is not pushing up and hurting them, therefore it is not reflux. The projectile vomit is then not a medical problem but more of a laundry problem. Congratulations, you have then been blessed with a Happy Spitter! Stock up on laundry detergent.
However, if your baby is in distress and unhappy while these vomits are coming out, you need to look into the possibility of reflux and it is then best to take your baby to the pediatrician.
The vomiting is said to get better after 6 months when you start to introduce solids, as the milk then mixes with the heavier and thicker food in the stomach and stay put more easily.
Just this weekend my little one had an "incident". Just as I texted grandma that we were on our way after placing her in her car seat, she had other plans. Bringing up almost all of her feed she had just nursed from me, covering herself, the car seat and even having a pool of vomit drip from the car seat and gather on the kitchen counter. Needless to say, we were late.
UPDATE: My little girl is now 6 months old and the vomit and spit up has almost completely stopped. She had the occasional wind now and then but hardly any vomit. It is also not necessary to burp her after feeds anymore, since about 4 months when she began to sit up, the winds came out by themselves.
If you suspect your little one has reflux, these articles might shed some light on it: