|MadSci Network: Engineering|
Bullet shape, velocity and material need to be considered when determining an effective bullet stopping barrier. Barrier thickness is a major factor in stopping a bullet. Other factors that are important are barrier shape (round or angled to the direction of the bullet), hardness and metallurgical chemistry of the barrier to achieve maximum hardness. For your application (for use in furniture), I would suggest a product called Kevlar which is used in the military and police units. Attached is a good article for your consideration.
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