What the heck is a “Vent-Liner,” anyway?
Well, I didn’t name it. It is simply a hollow hex screw at the powder end of the breech plug. I’d call it a “Flame Jet Screw.” They begin with a .030″ orifice, and erode with time. When they reach .040″ or so, they begin to affect ignition, and require replacement to insure “new gun” level accuracy. For most hunters, it is merely annual replacement. It is employed so breech plug replacement is not required, only the Flame Jet Screw (Vent-Liner). For those that shoot often, the specific amount of life of the Vent-Liner is contingent on the specific propellant, propellant charge, and projectile. One example is using a pound of Accurate Arms 5744 powder. That will net you in the area of 180 shots with full-powered loads. When you burn up that pound, it is the time to remove and service your breech plug, and replace the vent liner. My opinion is that is smart to back down 10% from the hottest loads. That naturally gives you 10% more shots per pound of powder, but cuts your muzzle velocitie
