When purchasing Loctite or any other brand from eGoods365.com store, you can be sure that (a) you are purchasing from US based company with the most responsive and friendly customer service; (b) an authentic, not a counterfeit and not a refurbished product.
Loctite 603 is intended for bonding cylindrical fitting parts, especially when clean surfaces cannot be guaranteed. This retaining compound hardens by confinement in the absence of air between closely fitting metal surfaces and prevents loosening and leakage caused by vibration and shock. Despite oil and other contaminants, 603 demonstrates particular tolerance. FNH suggests using this product to attach rail systems to SCAR and 16S/17S firearms.