Originally Posted by
Underclocked
I think I would want the whole 209 nipple to be new after that episode.
Probably not needed UC, popping the retainer spring is not uncommon thing.
The nipple itself is very strong - In this case the blow-bac pressure - pushed the primer back to the point it was able to get pregnant enough that a side blew out while still partially in the nipple and stretching the retainer spring to the point of distortion. Actually if you you took the time and had the right tools - you could re-bend the spring to the right diameter and re-install it.