We prefer to use the Magwell Safety Flags we design and sell..........BUT some sanctioning bodies won't allow it and you have to have something that actually inserts in the chamber.
We use a rare earth magnet on both parts. The chamber flag works on most bolt action 22lr and larger caliber rifles. They will NOT fit through the ejection port of an AR15 or 10/22.
The Cold Bore Cap should be installed right after you finish your course of fire and then obviously removed before you start your next round. This will help considerably with your first cold bore shot.
Fits up to 1.20" barrels
Shipping is included and comes via UPS