That's a thorough step by step Ron, and may be enough to discourage my going after one of the vented BPs. My bit selection, while bountiful, is tired from assorted tasks in a wide variety of materials. I probably should have put the $ for this gun into upgrading that stuff. Nah. I think for now I'll get a 21 carbide as SL suggested, tap the bare 209 BP from my Wolverine and tap the Disc plug after shooting it FPJ for a while, and keep an eye out for a Lehigh bolt adapter. Thanks

Other thoughts. Have you tried an extractor to remove the liner after removing the dome? Or drilling through completely with a larger bit, inserting a solid plug, and drilling & tapping the plug? Wonder if either of those would easier.

Your second idea may work good. One could run the 7/16" end mill about a half inch deep. Then turn a stainless cylinder to be a tight fit in the breech plug. Drill through with the # 21 drill. Countersink, and tap the plug.

Or, tap the 7/16 hole, screw in a stainless bolt, cut off, grind, tap and thread vent liner. Bolt being ready made plug.

yes indeed

the bolt technique
 

A few years ago i used a bolt to convert the FPJ breech plug to an NFPJ breech plug.
















More information at the LINK. It took me a few days to get things working right.

Looks like nice work, and a lot of it!

All 3 of my Knight Disc Extremes/Elite have been converted to use the bare primer. My current bolts have to use the original adapter piece and I use the Lehigh Breech Plug with solid vent tube. I've just ordered the new bolt/plug conversion from Knight and I'll let you know how it performs. I don't fire as many rounds every year as many on the Forum do and so far I've not detected any issues with my present set up that would require a new vent liner/plug. You will enjoy the Elite; its very accurate and a nice handling gun.

Are you ordering the bolt because you only have one adapter and have to swap it when changing guns, or because you aren't completely happy with blowback etc.?

I have an adapter for each gun. I was getting more blowback than I liked with the CCI 209M primer as well as the Federal 209A so I switched to Winchester's regular 209 primer(its a slight bit longer than the other 2) and that solved the blowback issue. My reason for the change was because I liked the larger opening for placing the primer in the new bolt. Received the parts Friday and made a quick trip to the range yesterday. Installed the new BP and bolt and could not get the bolt to close completely. Long story short I finally realized the primer was not seating completely(deep enough) in the primer pocket to allow the bolt to fully close. I reinstalled my old Lehigh BP with brazed vent tube and everything worked. I tried the 3 209 primers mentioned above in the new BP and none of them would seat completely in the primer pocket unless I exerted a lot of force pushing down with a short piece of 2 x 4. Needless to say they were hell to get out. Some where in the manufacturing process nobody checked specs etc. Will be in touch with Knight tomorrow. I'll keep you posted on what they say.