My DS2 had severe reflux so I am the world's expert on it.
He used to projectile vomit everything - breast milk, formula milk, even solid food.
He didn't put on weight for a while and then, when he did, it was very slowly.
At six months, when he sat up, it got much worse (because stomach is crushed more, therefore forcing stuff back up more).
When he learnt to walk (14 months), it stopped. (Upright and therefore not forcing everything up anymore).
We found that ranitidine worked a bit - probably stopped about 50% of the vomiting.
Oemeprazole or whatever it's called works brilliantly, but only comes in tablet form which is very hard to get down a baby, so we had to give up on that.
Anyway, the paediatrician who saw him said that our older son also probably had reflux. He used to vomit after most feeds, but only in a dribbly kind of way - not hitting the ceiling, like DS2.
Any of this sound familiar?