I had an IPA once that I bottled and it would not carb at all, even after a couple of months in a warm room. These beers were so flat - most had zero carbonation - that all I could conclude was that I forgot to prime when bottling - even though I could swear I remembered doing so. I figured I had nothing to lose so I opened all of the remaining bottles and poured them into a purged keg as carefully as possible to minimize any splashing and carbonated it in the keg. Once carbonated it tasted great, no oxidation. Everyone who tried it loved it and the keg was empty within a few days. Would I recommend doing this if you did not have to do so? No, but it can be done with good results, at least with some beers. I am brewing the same beer again this weekend, but this time it is going straight to the keg!