I think you might have two separate problems.
If the stud pulled out of your forend you probably have a tupperware stock. This being the case the best fix would be to bed a thin piece of steel in your forend, drill and tap the steel to match a threaded stud, then spin a lock nut onto the end of the stud where it comes through the piece of metal. The threaded portion of the stud must be short enough that it does not contact your barrel. Once it is all aseembled and tight, I would cover it with glass bed.
When you shoot, are the legs of your bi-pod on a hard surface? If so, it would be similar to shooting the rifle with the forend resting on a hard surface. Try putting a rubber mat, your gloves, or something else that would produce a soft barrier between the legs and the hard ground. This is also useful when shooting on a loose surface like sand where the legs tend to bury themselves from shot to shot.