Breech Plug - Vent Liner Project

[sabotloader]

Well since I retired again! and I am suppose to have more time - I tackled my next project... installing a Savage type vent liner in a Breech Plug - preferrably a BP that has been burned out. I got a selection of vent liners from Grouse last week.

Problem... I do not have any burned out BP's like that so I took a brand new Omega BP to a friends Machine Shop - explained to him my problem and my thoughts and he said lets go do it.

I thought he would take it to a drill press and complete the work, but he chose to put it on a lathe as he wanted every thing to be parrallel and he wanted to match the contour of the bottom of the Vent liner with a simular detent in the bottom of the breech plug.

After he took his measurements and got the information he needed he chucked the BP and went to work. It actually took him longer to chuck up the BP than it did to create the VL pocket in the BP, drill out the flash channel, then run a 10/32 tap in the new flash channel. He estimated the next one would take him 15 minutes - start to finish. I am still sure you could do almost as well on a good drill press - think Lee proved that.

The flash hole in the 'Domed' Lehigh liner is .032 and the one in the flat Savage is very very close to the same. I am actually thinking the domed liner might provide less blow back.

Now, if the weather would cool down I would run out to the farm and give it a try. Might be a few days. But I am convinced this is the way to salvage BP's - buying vent liners is a lot cheaper than buying BP's.

If this works as well as I think it might grab a new Knight plug and do the same thing...

Here are some pictures of the project...

Hope this helps explain the project....

 

[jsteurrys]

I have a couple of Knight DISC FPJ concave breechplugs with burnt out orifices that you could have for this project if you would like them. Let me know.

 

[sabotloader]

jsteurrys

j, I wouldn't mind modifying one or both of your FPJ's. Let me know if you would like to proceed. I do both of them send you one actually both eventually, but you could try one and I would try one - then send it to you.

 

[paia]

This looks great--have you had a chance to shoot the Omega plug and, if so, how did it do?

Do you run the bit all the way through starting from the primer end, or do you just drill deep enough to tap for your vent liner threads from the flash hole/powder end? #21 drill?

And how does the T/C Omega stainless tap? Did it "fight" you much?

Thanks a lot--this is real interesting.

 

[frontier gander]

got a bigger pic?

 

[Widude]

I have a used Knight plug someone drilled out, other than that it's fine. I wouldn't mind trying one if you do a few?

 

[Chick]

At what point, do you consider the BP to be "burned out"? When it burns out, is there any other effect besides blowback?

 

[sabotloader]

Chick

Look closely at you 'flash hole' each time you clean you BP when you start to notice an un-even hole or worn hole - you are reaching the time that you may want to consider either a new BP or installing a vent liner. Also with a worn 'Flash Hole' you may begin to notice loss af accuracy.

 

[Lee 9]

For the XT breach plug by TC users who also use Blackhorn.
I have modified several plugs now two XT and one Omega , actually the Omega was re modified after I picked up on using the vent liners from Sabotloader The on I had in it work as good as the original BP but not as good as the mod we are using now because done just right it reduces the carbon build up a lot. There may be a few slight differences in the way we do it for one thing I place the vent liner restriction right about where the original restriction is on the original TC plugs. The Idea that Sabotloader had about drilling all the way through is at least part of the solution to the carbon problem we are not really sure how much of that answer is due to the Lehigh vent liner considering what a pain they are to make and the fact that I only get about 25 % of the carbon I did before I am about done experimenting with it on the basis of not broke then don't try to fix it. Lee

 

[Chick]

The man at Blackhorn told me that they have the least amount of trouble, with BPs that have the larger hole extend the length of the BP, then it narrows down to the flash hole. I take it that you don't have this trouble? Do you think this can be incorporated on the Traditions Accelerator BP? It is flat on the powder side, not the Thunderdome style.[/img]

 

[drdtmd]

sb Very nice job. I've done Done quite a few plugs like this myself:encore,knight,genisis,and variuos custom plugs all with a press. I like the fact that you can control the flash hole to suit your needs. A .156 drill bit and a 3/8 countersink will do the job.of course the way you did it is much more precise but I get lazy from time to time to time and don't want to travel to my Buddys machine shop a hour away. I look forward to hearing about your shooting session.

 

[Lee 9]

Chick
I have not seen any BP yet that this mod could not be done on, BUT I have not seen the one you are talking about and because it would not phase me does not mean it would be a good idea for a person that did not have the right tools or experience. I have built and worked on many kinds of guns in the last 50 years. Do you happened to live near one of the old timers, well that would not be the right question. Some of the newer people are sharp machinists to. I guess you might ask if any one has modified one of them yet, from some of the e-mails and such it would seem that this is going to be a popular mod which considering the price of some BP like the XT is understandable. I suggest you start a thread with that question . Lee

 

[Chick]

Thanks. I would think that someone would make the vent liners out of a flat head screw, that has the same strength as the Lehigh liner does. If they did, I would not have a problem with that, but I am a bit worried about converting a flat face BP to a convex face.

 

[ronlaughlin]

Thanks. I would think that someone would make the vent liners out of a flat head screw, that has the same strength as the Lehigh liner does. If they did, I would not have a problem with that, but I am a bit worried about converting a flat face BP to a convex face.

I think you mean concave face, but perhaps you don't. If you truly mean convex face, one could do that by building up the face of the bp with weld, and then grinding it off, or cutting it off on a lathe.

If you meant 'concave' face one may be able to do this depending on the length of the flash hole. My Accura has a flash hole length of only 1/8" so there is no room to make a concave face. What i intend to do in order to end up with a concave face is install a vent liner in the Accura bp, and hopefully end up with a more reliable rifle using BH209.

 

[Morris]

When does some one go into Production sounds like a great idea.

 

[Chick]

Concave would go in, like the Traditions "Thunderdome" breech plug. Convex would curve outward. If you look at the Lehigh Vent Liners, you will see what I mean. If you do the work on the face of the BP, to install the Lehigh Liner, you will have the convex head protruding into the powder area. Not sure how this would affect the burning rate of the powder. If you look back on the Vent Liner project pictures, you will see that they were installing the vent liner in a recessed hole, and I think this recessed area, was here to begin with. On my BP, the face is flat. Maybe I could cut down into the face, and install the vent liner.

 

[ronlaughlin]

............................. On my BP, the face is flat. Maybe I could cut down into the face, and install the vent liner.

Exactly. This is what i intend to do with the Accura breech plug.

 

[Chick]

We have the same sublect in 3 threads now, and some of that was my fault. Sorry. I was talking about countersinking the BP face, and using a flat head vent liner, so that the BP was flat faced when I was through. Is there a thought why the domed Lehigh VL would be better? Should it be countersunk into the BP, or should the dome extend into the Powder Chamber? By the way, the 2 places I have found the VLs, they are $5 a piece. Where can you get them for $3?

 

[tpcollins]

I understand now what the vent liner is but I wouldn't 100% agree with the blunt end of the liner and it's ability to funnel the flame from the primer thru the hole. Then I stumbled across this link and it makes perfect sense to countersink the end of the liner towards the primer. Take note in the middle of the diagram pertaining to: "slight angled bottom to throttle flame to the powder charge". If I were making my own liners, I think I would countersink the end towards the primer too.

However, if there's no problem with them being flat, it's a moot point I guess. The other difference I see is the location of the flash hole is closer to the primer than on some of the ones shown in pics on the forum here - but I'm not sure if the illustration below would provide more blowback or let the flame scoot thru the flash hole easier.

http://www.hpmuzzleloading.com/Technical6.html

For reference, the XT plug on my BC has the flash hole about 1.423" from the bottom step where the primer sits. The article refers to the Knight plug as one of the best and it's passageway is only .970" long.

 

[sabotloader]

tpcollins

The plug that Toby is showing you in his diagram is the existing Knight FPJ plug. Which is the first plug on the left in my picture. It is a very reliable plug to shoot BH with - so I am sure Toby naturally selected it.

But, I am not so sure the second plug on the left would not actually be the better plug for ignition and reduction of blow back. You can see the domed face of the plug (convex face) this offers some deflection of the pressure being built up in the bore. Replacing that domed face with a Lehigh Vent liner offereing the same domed face but with the enlarged 'fladh hole' of the Lehigh would offer excellent ignition. And in the same way if you drill out the 'flash channel' to 5/32" it would also increase the volume of gas the BP can hold - reducing the blow-back effect twice...

Take a peek at this thread and my last post... might help with some ideas...

http://www.modernmuzzleloader.com/phpBB ... 694#121694