Savage Vent Liner in an Omega Breech Plug
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ronlaughlin
Busta has been working with the NEF BP for a long time and I am sure he has perfected what he needs there.
I am not sure about his thoughts on the depth of the vent liner in the BP. In the past when I have done one of these conversions - I usually install the vent liner at close to the original depth of the previous 'flash hole'
I thought for sure that when I recieved the new Lehigh breech plug for the Knight DISC series the vent liner would be near the top if not on the top of the plug to help push pressure off the cone to the sides of the bore.
If you look at this picture you can see how wrong I was.
Lehigh Dave, actully open the cavitiy to a larger diameter, notice how much room is available on the sides of the vent liner. And it is recessed much deeper than the the normal Knight FPJ plug.
At least from my side of the world I am not sure what or where the correct distance is or should be. Lehigh Dave did his experimentation and found his answer, Lee and I have done some as we work our way through this new thing and I believe you are on the verge of doing a good thing for CVA shooters - but you have to start some place. Maybe you will do the next one different...
Busta has been working with the NEF BP for a long time and I am sure he has perfected what he needs there.
I am not sure about his thoughts on the depth of the vent liner in the BP. In the past when I have done one of these conversions - I usually install the vent liner at close to the original depth of the previous 'flash hole'
I thought for sure that when I recieved the new Lehigh breech plug for the Knight DISC series the vent liner would be near the top if not on the top of the plug to help push pressure off the cone to the sides of the bore.
If you look at this picture you can see how wrong I was.
Lehigh Dave, actully open the cavitiy to a larger diameter, notice how much room is available on the sides of the vent liner. And it is recessed much deeper than the the normal Knight FPJ plug.
At least from my side of the world I am not sure what or where the correct distance is or should be. Lehigh Dave did his experimentation and found his answer, Lee and I have done some as we work our way through this new thing and I believe you are on the verge of doing a good thing for CVA shooters - but you have to start some place. Maybe you will do the next one different...
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Lee 9
yup!
yup!
Ron,
Didn't mean to ruffle any feathers, sorry if it sounded that way. I have been at this breech plug tinkering for several years. I don't post everything that I discover, but after nearly 2 years with Blackhorn 209, and approxamately 40-50 breech plugs, I do know what works for me.
You mentioned blowback in both of your tests, this is a big concern to me as well. The Omega plug is not perfect, there are several that have gas cutting in the bottom of the primer pockets. The vent-liner is not going to cure the blowback problem, it just makes it much easier to maintain a constant, or near constant flash hole. IMO, the blowback is related to ability of the primer to seal the pocket, while maintaining pressures that counter the pressure of the charge long enough to get the bullet out the end of the barrel. Again IMO, if you increase the diameter of the flame channel, then reduce the lenght, you also have reduced the volume the flame channel will hold. This increases the pressure, and blowback will follow the path of least resistance, usually through or around the primer. Primer length and diameter is also part of the equasion, I like 2 to 3 thousandths of compression on the primer rim for best results.
I gotta run, will try to add more input later, if it is welcome?
Didn't mean to ruffle any feathers, sorry if it sounded that way. I have been at this breech plug tinkering for several years. I don't post everything that I discover, but after nearly 2 years with Blackhorn 209, and approxamately 40-50 breech plugs, I do know what works for me.
You mentioned blowback in both of your tests, this is a big concern to me as well. The Omega plug is not perfect, there are several that have gas cutting in the bottom of the primer pockets. The vent-liner is not going to cure the blowback problem, it just makes it much easier to maintain a constant, or near constant flash hole. IMO, the blowback is related to ability of the primer to seal the pocket, while maintaining pressures that counter the pressure of the charge long enough to get the bullet out the end of the barrel. Again IMO, if you increase the diameter of the flame channel, then reduce the lenght, you also have reduced the volume the flame channel will hold. This increases the pressure, and blowback will follow the path of least resistance, usually through or around the primer. Primer length and diameter is also part of the equasion, I like 2 to 3 thousandths of compression on the primer rim for best results.
I gotta run, will try to add more input later, if it is welcome?
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Busta
Totally agree with everything in this statement - for what ever that is worth...
Busta, although I do beleive the Lehigh vent liner does help reduce some of the blow back pressure because of its cone shape. Instead of the pressure being funneled back down into the 'flash hole', a lot of the pressure is pushed away from the 'flash hole' so only a limited amount actually backs up into the the BP before the bullet departs the barrel.????
Again just thinking out loud...
Totally agree with everything in this statement - for what ever that is worth...
Busta, although I do beleive the Lehigh vent liner does help reduce some of the blow back pressure because of its cone shape. Instead of the pressure being funneled back down into the 'flash hole', a lot of the pressure is pushed away from the 'flash hole' so only a limited amount actually backs up into the the BP before the bullet departs the barrel.????
Again just thinking out loud...
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BUSTA
Sofar i like yours the best. Top pic and left plug that looks like a CVA type and the one below using the flat liner.
Just enough countersink on the powder side so pellets wont be damaged,,,,even though i dont use pellets. Mainly because it appears it might be more effective on blow back.
My Ovation has a flush type vent liner and it has almost zero blowback even with 300gr+ bullets, 120gr BH209 charges and Win209s. Ignition is awesome too.
A heavy counter sunk vent liner/BP will tend to throttle the gas backwards more IMO. The Lehigh liner in the CVA type should be great IMO and set just under flush.
Mines not bad but i do like being able to just replace only a vent liner and upgrade older breach plugs so they will last much longer.
Sofar i like yours the best. Top pic and left plug that looks like a CVA type and the one below using the flat liner.
Just enough countersink on the powder side so pellets wont be damaged,,,,even though i dont use pellets. Mainly because it appears it might be more effective on blow back.
My Ovation has a flush type vent liner and it has almost zero blowback even with 300gr+ bullets, 120gr BH209 charges and Win209s. Ignition is awesome too.
A heavy counter sunk vent liner/BP will tend to throttle the gas backwards more IMO. The Lehigh liner in the CVA type should be great IMO and set just under flush.
Mines not bad but i do like being able to just replace only a vent liner and upgrade older breach plugs so they will last much longer.
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Busta
You said,
It certainly is welcome. I have been playin' with breech plugs for two weeks; you for considerable longer. I need to learn to write more 'polite'. Discussing ideas with knowledgeable folk, is quite enjoyable for me.
My brief experience with the Accura, and it's very very seldom failure, led me to try and duplicate the Omega breech plug. In my mind, the Omega breech plug is 100% reliable. You feel the Omega breech plug has limitations. It seems you have sought to reduce blow back. My main goal is to increase reliability; blow back wasn't the major concern when i began the vent liner project.
You have expressed your opinion that a breech plug with the vent liner more or less flush with the end is better than having the vent liner recessed. My concern with this alignment is: will this be more reliable in the Accura? The flash channel certainly will be longer in your idea of the 'best' breech plug. This, naturally, will increase the volume. However, i keep wanting to increase the size of the powder pocket, because i am searching for reliability.
I am going to do a little arithmetic on the volume of the fire channel in the Accura breech plug, and post back here later.
You said,
It certainly is welcome. I have been playin' with breech plugs for two weeks; you for considerable longer. I need to learn to write more 'polite'. Discussing ideas with knowledgeable folk, is quite enjoyable for me.
My brief experience with the Accura, and it's very very seldom failure, led me to try and duplicate the Omega breech plug. In my mind, the Omega breech plug is 100% reliable. You feel the Omega breech plug has limitations. It seems you have sought to reduce blow back. My main goal is to increase reliability; blow back wasn't the major concern when i began the vent liner project.
You have expressed your opinion that a breech plug with the vent liner more or less flush with the end is better than having the vent liner recessed. My concern with this alignment is: will this be more reliable in the Accura? The flash channel certainly will be longer in your idea of the 'best' breech plug. This, naturally, will increase the volume. However, i keep wanting to increase the size of the powder pocket, because i am searching for reliability.
I am going to do a little arithmetic on the volume of the fire channel in the Accura breech plug, and post back here later.
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Hows this for thinking out loud.
Ok...say you mod a breach plug with a vent liner for using BH209.
Now that you have a threaded portion in the powder side, wouldnt it be possible to turn it into a "Power Stem" for T7 users too?
Just swap out the liner for a short stem? Ive never seen the older Knight Power Stem in person so i dont know but......everything ive read showed a nice fps boost and a positive impact on the crud ring.
Now you have a quick convertible plug that will use both powders to the best of their ability.
Sorry if it was just a brain fart and not a thought
Ok...say you mod a breach plug with a vent liner for using BH209.
Now that you have a threaded portion in the powder side, wouldnt it be possible to turn it into a "Power Stem" for T7 users too?
Just swap out the liner for a short stem? Ive never seen the older Knight Power Stem in person so i dont know but......everything ive read showed a nice fps boost and a positive impact on the crud ring.
Now you have a quick convertible plug that will use both powders to the best of their ability.
Sorry if it was just a brain fart and not a thought
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Busta said:
Repeating myself...........your input is more than welcome. Your statement about length and diameter and volume drove me to do some arithmetic. A simple truth about the volume of a cylinder which is basically what the flame channel is, goes like this: If you double the length of a cylinder you double the volume. If you double the diameter of a cylinder you quadruple the volume. What this means is: If You double the diameter of a cylinder and halve the length, you end up with double the volume.
This bit of trivia sent me out to measure the modified Accura breech plug, and the new Accura breech plug.
The length of the flame channel in the new unmodified Accura breech plug is 0.77". The diameter of the flame channel is supposed to be 3mm, which is .118". So, doing the arithmetic one finds the volume of the unmodified breech plug flame channel is 0.0084 cubic inch.
The length of the flame channel in the modified breech plug is 0.37", and the diameter of the flame channel is made by a #21 drill which is .159". The volume of the flame channel in this plug calculates to be 0.0073 cubic inch.
It turns out the volume of the flame channel of the modified breech plug is just a bit smaller than the volume of the unmodified breech plug. In order to make the volumes the same the flame channel would have to be 0.42" long in the modified breech plug. This would reduce the length of the powder pocket by 0.05", which now is about 0.25" when using the Savage vent liner.
I guess at this point i am inclined to make the powder pocket about half as deep, which would increase the volume of the fire channel and make it a bit larger than the volume of the unmodified breech plug fire channel.
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GM54-120
Almost hate to show you this... but take a look...
On the left a Savage Vent liner... in the Center A Lehigh Extended center fire Vent Liner and on the right a standard Lehigh Vent Liner...
Almost hate to show you this... but take a look...
On the left a Savage Vent liner... in the Center A Lehigh Extended center fire Vent Liner and on the right a standard Lehigh Vent Liner...
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sabotloader said:GM54-120
Almost hate to show you this... but take a look...
On the left a Savage Vent liner... in the Center A Lehigh Extended center fire Vent Liner and on the right a standard Lehigh Vent Liner...
OK NOW you got my attention.
That plain rocks....sign me up. :yeah:
Ron,
If you are just looking for pure 100% reliability igniting BH209, with any 209 primer you choose, then the Metrics Unlimited style plug is IT! Now remember, this style plug goes against everything the major manufacturers are using. This is "outside the box" engineering. I have a few, OK quite a few of these plugs. Nick designed these plugs to shoot 777 powder initially in the H&R/NEF Huntsman and Sidekick. The standard H&R/NEF plugs utilize a plastic orange primer carrier for the 209 primers, the MU plug is a bare 209 primer plug.
Standard Plug, with primer carriers on left, hubbard 209 plug on right.
What is unique about this MU plug, and different from anything else on the market, is that it actually has no flame channel. The bottom of the primer pocket funnels directly into the flash hole. The flash hole is .042" in diameter and approximately .200" long, and it dumps directly into the powder pocket on the other side. By adding an o-ring in the bottom of the primer pocket, this improved the primers ability to seal the pocket.
I have been doing extensive testing with this style of plug, and with my o-ring mod, have not found anything to light BH209 better, and as I said earlier, with any primer, even the Remington 209-4 (410 primer) and all the reduced charge ML primers.
38 shot range session with BH209 and Win ML primers. Notice the 2 cent o-ring, before and after. The primer carriers for these rifles are $15 for 10, which each one can be used approximately 20 times, but blowback is severe from the very first shot, and progressively gets worse. So basically it would have been 2 primer carriers for this range session at $3, or the 2 cent o-ring that actually seals and works on BH209 100%. The primer carriers are also not reliable for BH209, even with a brand new one.
IIRC, I have tested 11 different 209 primers with the MU plug an BH209, not even a hiccup, ever! The pics show how clean the BP is after a range session with BH209.
Pay close attention to this pic, this is after an extended range session, around 40 shots or so, notice how little carbon is in the bottom of the primer pocket on the ID of the o-ring.
Just another way to skin a cat. :wink:
If you are just looking for pure 100% reliability igniting BH209, with any 209 primer you choose, then the Metrics Unlimited style plug is IT! Now remember, this style plug goes against everything the major manufacturers are using. This is "outside the box" engineering. I have a few, OK quite a few of these plugs. Nick designed these plugs to shoot 777 powder initially in the H&R/NEF Huntsman and Sidekick. The standard H&R/NEF plugs utilize a plastic orange primer carrier for the 209 primers, the MU plug is a bare 209 primer plug.
Standard Plug, with primer carriers on left, hubbard 209 plug on right.
What is unique about this MU plug, and different from anything else on the market, is that it actually has no flame channel. The bottom of the primer pocket funnels directly into the flash hole. The flash hole is .042" in diameter and approximately .200" long, and it dumps directly into the powder pocket on the other side. By adding an o-ring in the bottom of the primer pocket, this improved the primers ability to seal the pocket.
I have been doing extensive testing with this style of plug, and with my o-ring mod, have not found anything to light BH209 better, and as I said earlier, with any primer, even the Remington 209-4 (410 primer) and all the reduced charge ML primers.
38 shot range session with BH209 and Win ML primers. Notice the 2 cent o-ring, before and after. The primer carriers for these rifles are $15 for 10, which each one can be used approximately 20 times, but blowback is severe from the very first shot, and progressively gets worse. So basically it would have been 2 primer carriers for this range session at $3, or the 2 cent o-ring that actually seals and works on BH209 100%. The primer carriers are also not reliable for BH209, even with a brand new one.
IIRC, I have tested 11 different 209 primers with the MU plug an BH209, not even a hiccup, ever! The pics show how clean the BP is after a range session with BH209.
Pay close attention to this pic, this is after an extended range session, around 40 shots or so, notice how little carbon is in the bottom of the primer pocket on the ID of the o-ring.
Just another way to skin a cat. :wink:
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Busta..................................... sabotloader
Wow! Now this is gettin' real interesting.
Wow! Now this is gettin' real interesting.
Two different principles both work when applied right. If there were some real sharp manufactures keeping track of us the potential for a new rifle is here with the proper amount of research of course.
I would like to see a new rifle that use the barrel with a length that use the newer better powders with maximum efficiency also. Some thing really well thought out that added a bit to the sport.
I have often wondered if a gain twist could handle a wide range of bullets better, some thing that would handle conicals, and PRB as well as sabots with max efficiency.
I would like to see a new rifle that use the barrel with a length that use the newer better powders with maximum efficiency also. Some thing really well thought out that added a bit to the sport.
I have often wondered if a gain twist could handle a wide range of bullets better, some thing that would handle conicals, and PRB as well as sabots with max efficiency.
Lee 9 said:
Lee,
The "web' thickness is an approximate in my last post. If I understand what you are asking? I don't have exact measurements off the top of my head, if that is what you are asking?
One thing to remember, the primer is the weak link (structurally) with this type of conversion. And we all know that all primers are not created equally.
I would only use this type of conversion in a standing breech (tip-up), or solid bolt action type rifle. DO NOT TRY THIS IN A PLUNGER TYPE RIFLE, NON LOCKING BOLT ACTION, OR OMEGA/KODIAK DROP BREECH, OR SWING BREECH STYLE RIFLES! There is plenty of primer thrust, because it seals so well, and that is your WARNING!
Thanks for the info.
Understand about the action. Thinking about trying a method I know with an XT breach plug in my Encore. I like the idea of using the volume of the powder space for the primer burn, that works very well in cartridge guns and if it was set up right it just might give a more consistent powder burn. Lee
Understand about the action. Thinking about trying a method I know with an XT breach plug in my Encore. I like the idea of using the volume of the powder space for the primer burn, that works very well in cartridge guns and if it was set up right it just might give a more consistent powder burn. Lee
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