Call of Duty Wiki
Call of Duty Wiki
The subject of this article appears in Call of Duty: Modern Warfare (2019)
"Bullets slow enemy movement and briefly disable tactical sprint when shooting legs."
— in-game description

Frangible - Disabling is a Weapon Perk that appears in Call of Duty: Modern Warfare. 

Alongside performing the stated benefits, getting shot with the attachment will cause the borders of your screen to flash, not unlike a Stun Grenade. This may potentially disturb your aim with weapons like Sniper Rifles.