A grandchild does not have any birth right in the self- acquired property of his grandfather if it has been allotted to his father in a family partition in his capacity as legal heir and not as a coparcener under the Hindu Succession Act 1956. The grandfather can transfer the property to whoever he desires.
If the Grandfather dies without leaving any will, then only his immediate legal heirs i.e. his wife, son(s) and daughter(s) will have right to inherit the property left behind by him.
As the properties inherited by the wife, son(s) and daughter(s) of the deceased would be treated as a personal property of those who inherit the same, no one else has any right to claim any share in the same property.
In case any son or daughter of the grandfather dies before his death, then the legal heir of the predeceased son or daughter will get the share which the predeceased son or daughter would have got.
The grandchild of the grandfather shall be entitled to get a share of his/her predeceased father only but if the father is alive then she/he is not entitled to any share
source:
Advocate Chikirsha Mohanty, lawrato