5/16 X 32; 1/4 x 32; 3/8X32 thread. From Jim Chambers. Extra large, deep inside cone improves ignition. Unit is installed using a vice grip, then shoulder is cut off with a hacksaw.

The large cone of this touch hole liner brings the flash to with in a few thousandths of an inch of the main powder charge which will noticeably decrease the ignition time with flint locks. 5/16x32 No. 23002    1/4x32 No. 23004 3/8x32 No. 23005. Also available in a Carbon Steel to accept bluing or browning to match the barrel finish. No. 23006 5/16x32 Carbon Steel; No. 23007 1/4x32 Carbon Steel