Knight and TC breech plug questions??

[heavybarrel]

I have recently purchased a new Knight Ultra Light, and have owned a TC Pro Hunter for years. I posted a question on suggested loads for the knight and got some great responce as I always do on this site. I have been researching the forum for information about my new riflle and have ran across post about bushining and installing vent liners in the Knights and I am interested, but somewhat confused on the matter. I was about to send my Pro Hunter breech plug to Ron Laughlin, excuse the spelling, for him to drill and tap my old breech plug to accept vent liners when I read that the primer side will also develope issues?? What happens to the primer side and when do I know its bad??

My next question is with the new Knight breech plug. I have been reading about bushining and cutting the braze vent liner out and using after market vent liners?? What is recommend and how is the processes done and can you please explain both.

Thanks is advance

Heavy Barrel

[ronlaughlin]

What happens to the primer side is the seat gets flame cut sometimes. Once the seat is flame cut it leaks blow by, and gets cut more and more. Keeping the flame channel clean helps keep pressure lower, and helps stop the flame cutting from occurring. As the size of the flash hole grows, so does the pressure on the primer, which increases the chance of the flame cutting.

Removal of the brazed vent liner i have done three times. Each time it was difficult, and i never learned a good system to do the job. The brazed vent liner is very very hard, and my drills were always dulled no matter how i went about it, and it never was easy for me. Perhaps a real machinist would know how to do this job and/or learn how to do this job, but i never really learned much, except that it was difficult for me. Once the brazed vent liner is removed, it is an easy task to chase the threads with a 10-32 tap, and utilize a removable replaceable vent liner.

There are available some breech plugs that have removable vent liners. If you can find the source, this would be a good deal.

[bestill]

If you like to consider bushing.. set up breech plug in vise with v block on mill and find center then use .250 carbide end mill plunge cut to depth of .562 then tap hole with 5/16x24 to depth of .312 or 9 revolutions.. your ready to install bushing and use a hollow socket set screw5/16x24. Bushing available from Luke at arrowhead sporting goods..with ventliner and proper headspace or sealing of primer . Primer pocket issue should be resolved. Id start with a new plug and keep flame channel clear. Flame channel minimum id .140 to max .156.

[mrbuck]

These guy's know everything !

[ronlaughlin]

After reading bestill' post i realized i neglected to mention that i used to normally run a 5/32" drill to the end the flame channel of new Omega breech plugs, before i used them. What this does is increase the volume of the flame channel, which in turn reduces the pressure on the primer, which in turn reduces the chance of a flame cut primer seat.  Also, what happened to me from time to time, was the heavier loads of powder would push blow by, right through the middle of the shotgun primers.  Enlarging the diameter of the flame channel,  stopped the blow by though the primer, until the diameter of the flash hole grew large enough, to allow too much pressure on the primer.

However, these past few months, since i started using large rifle magnum primers, i no longer change the diameter of the flame channel. Reason is because the large rifle magnum primers are more able to withstand the pressure of burning Blackhorn powder; they don't leak.

All of the more recent Knight plugs come with 5/32" diameter flame channel.

Over the years, it seemed, no matter what i did, eventually the primer seat would get flame cut.  This led me to use an o-ring between the primer, and the primer seat.  In CVA rifles, one just puts a metric o-ring in place, and load and shoot just like normal.  However, the TC rifles of mine, required one to make the primer socket deeper in order to successfully use the o-ring.  If one pays attention one doesn't need to begin using the o-ring, until the primer seat just so barely gets flame cut.

These days, i am using a breech plug modified to use the PR Bullet, primer adapters, which use large rifle magnum primers, and then further modified to allow the use of an o-ring between the adapters, and the breech plug..  The o-rings are good for about 30 shots, and they guarantee zero blow by, and thus no flame cut primer seats.  The use of large rifle magnum primers also results in zero erosion of the flash hole.  Shot gun primers seem to ruin a flash hole by about 200 shots, but  using the rifle primers has resulted in zero flash hole wear in around 360 shots so far...

[heavybarrel]

Very informative! Thanks

Does anyone know where one might be able to purchase an already modified Knight plug?

Heavy Barrel

[bestill]

Does ultra lite use same bolt handle and breech plug as mountaineer for bare primer setup. ?

[heavybarrel]

I am under the impression that it does.

Heavy Barrel