Seating the Lehigh Breech Plug

sabotloader · 05-04-2010, 06:38 PM

It occurs to me that one thing that might be causing a problem with the fit of the Lehigh Breech plug in a Knight rifle might be the carbon build up on the Breech Plug seat in the barrel of the rifle. I, for the lack of a better term, call it the barrel flange.

This shelf in the barrel is very suseptible to the build up of carbon debris. And it can be very difficult to clean. But in the case of the Lehigh it can be significant. The plug is designed with very close tolerances to fit the Extreme/Elite series of rifles. If the Breech plug does not or can not seat with the face of the Breech Plug squarely and flatly on the barrel flange it can cause a problem when you attempt to close the bolt as the stem will contact the rim in the primer adapter and will not allow the bolt to close.

This drawing shows how the face of the Breech Plug should seat on the face of the barrel flange. If there is a build up of gunk on the flange then the breech plug is pushed out a few thousands... with the tight tolerances of the Lehigh this can interfer with the closing of the bolt....

These pictures although are not very good illustrate the point in the importance of cleaning the flange in the barrel...

In some of the Knight's this build-up can make it difficult to close the bolt as the Breech plug stem contacts the primer shelf in the primer adapter.

Hope this makes some sense...

rt_con · 05-05-2010, 04:48 AM

Thanks for the info sabotloader and UC !

Just want to say I had the same issue with the buildup you described... and it impacted both the Lehigh and Knight NFPJ plugs.

Gm54-120 · 05-05-2010, 05:13 AM

That is how i wrap my breach plug and clean the mating surfaces. Just that little bit of tape overlap on the front of the BP made a difference in keeping the threads cleaner too.

Just a fraction of a turn made a difference between go and no go with my GenI. The Gen II does fit and work better in the two of mine ive partially tested.

Sofar im very impressed with the fit of the Gen II in the Elite 45. Its much better in the Elite 45 than the Gen I in terms of primer head spacing.

IMO its nearly perfect (with Win209s) which could mean in some rifles it my be tight depending on primer ect. My Elite was the "loosest" of the 3 DISC based rifles i own.