ronlaughlin

This month has seen 2 different deer seasons. First one was an early doe season; second a muzzle loader season. Next month starts our general rifle deer season. This morning was a time for me to shoot the rifles i planned to use this upcoming season. The early doe season saw me use the 45 Knight Disc Elite successfully. It shoots a long way that rifle does. The muzzle loader season that ended yesterday required iron sights, and the X7 was used; results were good. This morning i tried out the 50 Knight Disc Extreme, and an X7 that is scoped.

Returning home, the Knight was cleaned, and whilst the new NFPJ breech plug was removed, i measured the flash hole. The flash hole measured 0.035". I counted the primers fired in this plug, and came up with 106. This is the second NFPJ plug i purchased from the new Knight. The first plug' flash hole showed 0.035" when i cleaned it after 108 shots. In the first plug i replaced the brazed vent liner with one made from Holo-Krome screw. In the above photo, the modified first plug is shown right of the newer unmodified plug. One can see the flash hole in the unmodified plug is definitely larger than the flash hole in the home made vent liner. As written before, the flash hole in the plug on the left is now 0.035". The flash hole in the plug on the right is 0.028" which is what it was new, and what it is now, after 37 shots.

It was decided to replace the worn vent liner in the new plug. The first time i did this modification, i used a 5/16" center drill to do the job. This preserved the dome effect. Today i decided to use a 3/8" spot drill which would completely remove the brazed in vent liner, and also because it was carbide. It seemed to me the carbide drill would better handle the hard existing vent liner.







One can see in the photo, the damaged cutting edge on the carbide spot drill. These carbide spot drill aren't cheap.







The breech plug was worked with the 3/8" spot drill, and a 5/32" drill, and a 10-32 tap to receive a new vent liner. The photo shows chatter marks left by a dulled spot drill. The Holo-Krome vent liner is shown to the right. It has a 0.028" flash hole. I know from experimentation that a 0.028" flash hole will ignite BH209 at every temperature i have tried. Regular primer will ignite BH from -17 degree up to 95 degree through a 0.028" flash hole, without failure. Larger flash hole are unnecessary, and only lead to a quicker breech plug/vent liner demise.





The last photo shows the newly modified plug, with vent liner in place, left of the plug that was modified quite some time ago. Both vent liner have a 0.028" flash hole at this time. Time and more shooting will reveal how well they survive the heat of ignition.

mountaineer magic

So, what gets the call for general rifle season? The Knight disc extreme? Or the Elite? For me it is definitely gonna be the Mountaineer

HEAD0001

Ron I read your post three times. But I don't understand. Why did you do this?? Were you wearing out the factory breech plug with 100 shots?? Is that what you are saying??

It looks like you countersunk the hole so the small screw would fit. That looks like a real nice job you did.

I assume by showing the nicked up bit that you are trying to say how hard the steel is in the breech plug??

How many shots do you get from the screw in place??

Just trying to understand. Thanks, Tom.

flounder33

Even if his ventliners wear out just as fast as the ones that came from Knight he now has the option of replacing just the ventliner instead of buying the whole dagum breech plug. Nice work as usual Ron.

Muley Hunter

Ron........Have you messed with the new BH 209 BP plug from CVA at all?

I ordered one with my new Optima. Just curious how good it is?

ronlaughlin

In the timber, in the black hills; today the call is the scoped X7. This isn't the rifle i had Monday, but it shoots as accurately or some better. The extreme had a chance this morning, but it made a 12" 3 shot group at 200 yard, whereas the X7 was shooting mighty fine. Your extreme gets another chance in the morning, but it just doesn't look good. Seems i will have to glasbed it this winter, after season, or some such thing.

It makes me sad to realize i messed up your chance at the 6 point, but i didn't see you. Then of all things, you helped me with my deer, which made my life more better.

mountaineer magic

Don't feel bad . I am glad you were able to come down and hunt. I was glad to actually meet a fellow forum member in person. if you ever want hunt this area let me know . There are a few farms I have permission to hunt. Thanks for the offer during Mt Lion season. If my sleeping bag fails me I might take you up on it.

ronlaughlin

It seems that hardness does not equate to erosion resistance. When i made vent liner from stainless steel screw, they didn't seem to be as hard as Lehigh vent liner, but they are far more resistant to erosion when used as a vent liner. The Holo-Krome screws i am now using seem to resist erosion as well as the Lehigh vent liner in these Knight breech plug, but they aren't near as hard. Nothing i have worked with has been as erosion resistant as stainless steel, but them screws are so very hard to drill, i decided to use Holo-Krome for my own personal use.

To make one vent liner from stainless steel screw might take 1 drill, and 1 screw, or 5 drill, and 5 screw, depending on luck or perhaps how i hold my mouth.

I can make 20 vent liner from 20 Holo-Krome screw using just 1 #70 drill.

ronlaughlin

There was a fella on these forum that offered his Apex plug for $10, because he didn't like it. I wanted to see what CVA was selling to ignite BH, so i purchased it. I have never seen the Optima plug. If it is like the Apex plug, i don't care for what CVA decided to sell.

In my opinion, the BH plug would have been much better with a powder cavity half as deep. This would have resulted in perfect ignition of BH in all temperature. The BH209 Apex plug i have in hand would have been near perfect geometry with a powder cavity half as deep.

Then, after CVA made the powder cavity too deep, they left the flame channel too small for such a short length. The flame channel diameter would have been perfect for the long length of the plug with a half as deep powder cavity. The flame channel as short as it is now, in the plug i have, should be 5/32" diameter.

The Optima plug i modified for you is/was 'optimal'. Of course this is only one man' opinion, however the opinion was formulated by wearing out the barrel of an Accura. You should have kept it. An added benefit of that plug was, when the flash hole eroded to be too large, you could have installed a new vent liner. By adjusting the firing pin bushing to achieve zero blow by, and thus not allowing flame cutting of the primer seat, replacing the vent liner would result in a lifetime breech plug.

Muley Hunter

I loved the one you did for me. It was a fast decision to sell the gun, and I didn't have another BP to put in it. Sorry.