A) Get the Lehigh plug and extra vent liners
B) Get some plain old Win209s
C) Get a 5/32 hex head drill bit to keep the flash CHANNEL clean. Old Knight plugs are probably a 1/8" channel if you want to clean them out. New plugs might be a 5/32 also.


Install the plug and adapter in the bolt.
Measure the length of a few primers and write it down
Insert each primer in the action with the Lehigh plug and close the action. DONT FIRE THEM
Remove each primer and measure them again.

Are they now shorter than new?
If you got atleast a .002-.003 crush you will be ok but some primers might have a tiny bit of soot after firing them. A .004-.005 crush is ideal.

When setup correctly a Lehigh plug will fire off BH209 with even the weakest of primers...I know...ive done it many times for testing but would never use them under cold hunting conditions.