Polythene to stop a military rifle? - Yes

Ever had a full scale tantrum trying to get the damn wrapping off? . It has a resilience better than steel if made in high tenacity grade

Polythene is a short name for Polyethylene. It’s been around since 1932, but didn’t really become a household name until the early ‘60s
It’s resilience to blunt penetration has long been taken for granted. A mere carry bag can resist immense force. Another variant of polythene is used in our “Ultra Light” body armour vests and our police anti-slash gloves

HAP-2 - NIJ Level III Polyethylene Plate

NIJ Level III is standard issue to conflict zone personnel. The ammunition listed above is typical of a war zone. The M80 NATO round is the official test shot, others are rounds we have tested on behalf of our customers.

At 1.4 Kgs per plate, the polyethylene plate is our lightest plate. It is suited to assignments where weight and mobility are critical.

Stab Vest, Stab Vests, Stab Proof Vest and Stab Proof Vests are common terms for body armour with a defined level of resistance to a knife or pointed weapon. The same also applies to bullet proof vest terminology - bullet proof vests have a defined level of ballistic resistance.