Flash Hole Liner, often called a vent, vent liner, or touch-hole liner.
Known as the White Lightnin' vent, the special 5/16-32 fine threads allow an extra large concave cavity inside, for use on 13/16" to 1" octagon barrels. Made in the USA, stainless steel, with removable lug for easy installation. Simply drill out your existing vent hole with out tap drill, thread the hole, lightly chamfer or debur the perimeter, screw this vent in tight using the extended lug, hacksaw the lug using the alignment slot, and file the vent smooth to the barrel. Gunsmiths can mill this vent smooth, without touching the existing finish. A small amount of Birchwood Casey's Choke Tube Lube on the threads will allow easy removal, if the vent orifice ever becomes enlarged.
Concave inside, this vent liner brings the main powder charge very close to the incandescent heat of the priming flash. Position the vent on the center of the pan, slightly above the pan to frizzen joint, sometimes called the "sunset" position. Covered by the frizzen when closed, the hole is a window centered on the heat of your priming flash, for instant ignition, without the whoosh-bang delay, seen in many flint guns.
Only the better quality London made guns were factory fitted with vent liners, but nearly all flint guns were later fitted with vent liners, after the vent hole in the barrel became worn from flash erosion, corrosion, or the aggressive use of a vent pick.
Order our #TAP-5/16-32-P tap, #DRILL-I tap drill, and #DRILL-CS-90-5 90° 5/16" countersink, to install this special thread 5/16-32 thread vent.