Page "Bag of holding" Paragraph 11

In the physics of Dungeons & Dragons, putting a bag of holding inside a portable hole will result in a rift to be opened to the Astral Plane, and both items will be lost forever.

If a portable hole is placed within a bag of holding, it instead opens a gate to the Astral Plane, sucking in every creature in a ten foot radius, and destroying both the bag and hole.

The contents of the bags are either scattered throughout the Astral Plane or destroyed.

Placing bags of holding into one another ( or within a Heward's handy haversack or vice-versa ) has no adverse effects in the current edition of the game and would allow one to store an unlimited amount of items by storing bags of holding within bags of holding, potentially nested ( each bag of holding being limited in total weight capacity to roughly 40 additional bags, depending on the size of each ).