I am not a machinist; just an old retired carpenter is all. They cost about $33. The dissection of your rifle was instructional for me too. I wondered why i have zero blow by around the primer in my Triumph, when i use W209.

Getting the plug perfectly centered is what makes the job be good. I don't have a spot drill; use a 3/8" 82 degree counter sink as the final step before tapping. Here is a plug headed to Michigan i guess. It was worked this afternoon after returning home from a hunting trip in bitter cold wind.







I laid that vent liner along side, in case you couldn't tell i am using them Lehigh.

Great day in the morning!