A ballistic vest or bulletproof vest is a piece of personal armor that helps absorb shocks, reduces or stops the penetration of the body by projectiles and exploding shrapnel fired by firearms, and is worn on the torso.
Soft vests are made from multiple layers of woven or laminated fibers and can protect the wearer from the small-caliber pistol and shotgun bullets, as well as fragments of explosives such as grenades.
These vests usually have bulletproof panels inserted into the vest. Metal or ceramic plates can be used with soft vests to provide additional protection against rifle bullets.
Metal components or tightly woven fiber layers can make the soft armor resistant to stabbing and slashing from knives and similar close-range weapons.
Soft vests are typically worn by police forces, ordinary citizens at risk of being shot (e.g., state leaders), security guards, bodyguards, while combat soldiers, police mobile units, and hostage rescue teams. Mostly wear rigid-panel reinforced vests, 
Body armor can combine bulletproof vests with other protective clothing such as combat helmets. Vests for police and military use can include ballistic shoulder and side protection armor components. Bomb disposal officers wear heavy armor and helmets with face shields and spine protection.
Bulletproof vests use multiple layers of solid fibers to “catch” and deform the bullet, making it mushroom-like and spreading its force over a larger portion of the vest’s fibers. The vest absorbs the energy of the deforming bullet, causing the bullet to stop before fully penetrating the fabric matrix. Some layers may be penetrated, but as the bullet deforms, the energy is absorbed by larger and larger areas of fibers.
While the vest prevents bullet penetration, the vest and wearer can still absorb the bullet’s impact. Even without penetration, a heavy bullet is enough to cause blunt force trauma at the point of impact.
Vest specifications often include penetration resistance requirements and limits on the amount of impact force delivered to the body.
On the other hand, some bullets can penetrate the vest but still cause low damage to the wearer due to the loss of velocity and their small mass/shape.
Vests designed for bullets offer little protection from sharp weapons (such as knives, arrows, or ice axes) or bullets made of non-deformable materials (such as those that contain a steel core instead of lead).
That’s because the impact of these objects is concentrated in a relatively small area, allowing them to pierce the fiber layers of most ballistic fabrics.
In contrast, stab vests offer better protection against sharp tools but are generally less effective against bullets.
Textile vests can be augmented with metal (steel or titanium) and ceramic or polyethylene panels for extra protection for vital areas.
These rigid armor plates are proven effective against all pistol bullets and rifles. These upgraded bulletproof vests have become the standard for military use, as soft body armor is ineffective against military rifle bullets. Correctional and police officers wear vests to protect against edged weapons and sharp objects. These vests may include coated and laminated para-aramid fabrics or metal parts.
