LBE Unlimited ARCW-5.56 Crush Washer Black 5.56x45mm NATO AR-15
https://www.tandktactical.com/shop/765857617459-lbe-unlimited-arcw-5-56-crush-washer-black-5-56x45mm-nato-ar-15-24524
https://www.tandktactical.com/web/image/product.template/24524/image_1920?unique=f20a432
This Standard Crush Washer is compatible with your 5.56 AR-15.
