Vent size and powder

[flatcreek]

Was having consistency problems with my 50 cal Lyman trade gun. Hanshi's post in another thread NEED SOME ACCURACY HELP about vent size and inaccuracy got me thinking. That when your rifle self primes a bit it may be leaving a void inside the vent liner, this may be causing a lag and some or all of my problems. I was using 3f swiss and had around 1/16 vent. It would dribble some powder out most of time and originally I thought that was a good thing, but Hanshi's post made me think it may be better to have the powder piled against the door trying to get out. I tried 2f Goex and no more self prime and it was like a different gun, felt like much more consistent lock time and the targets were definitely better.
I wanted to pass this info along as to my thoughts and see what others may think. ( Am I imagining things or not. )

 

[Grenadier1758]

No, @flatcreek, you are not imagining things. Your observations are real. I would not have expected to see Swiss brand 3Fg powder dribble through a 1/16" touch hole. I would have expected to see a few grains at the touch hole (against the end of the touch hole trying to get out). I would not expect to see self-priming until the touch hole is slightly larger than 5/64". If you have a set of number drills, measure the diameter of the touch hole. Since your ignition speed has improved and your target accuracy has improved, I would continue shooting as it is, but do determine the touch hole diameter.

 

[wiscoaster]

Thanks for the report. Makes perfect sense to me.

 

[flatcreek]

No, @flatcreek, you are not imagining things. Your observations are real. I would not have expected to see Swiss brand 3Fg powder dribble through a 1/16" touch hole. I would have expected to see a few grains at the touch hole (against the end of the touch hole trying to get out). I would not expect to see self-priming until the touch hole is slightly larger than 5/64". If you have a set of number drills, measure the diameter of the touch hole. Since your ignition speed has improved and your target accuracy has improved, I would continue shooting as it is, but do determine the touch hole diameter.

Thanks for the comment. The touch hole is .060 a 1/16 drill won't fit and a .060 drill will just go in and I think that's what I drilled it with. I also have the outside countersunk a bit which make for a short channel and may make it easier to get out. Piled against the hole is what I want. I'm thinking that if your going to use 3f .050 or .055 may be the correct size. I have a .40 cal I use 3f in and am considering changing the vent in that as it is also .060. It's not a patent breach which also may make a difference.

 

[M. De Land]

Was having consistency problems with my 50 cal Lyman trade gun. Hanshi's post in another thread NEED SOME ACCURACY HELP about vent size and inaccuracy got me thinking. That when your rifle self primes a bit it may be leaving a void inside the vent liner, this may be causing a lag and some or all of my problems. I was using 3f swiss and had around 1/16 vent. It would dribble some powder out most of time and originally I thought that was a good thing, but Hanshi's post made me think it may be better to have the powder piled against the door trying to get out. I tried 2f Goex and no more self prime and it was like a different gun, felt like much more consistent lock time and the targets were definitely better.
I wanted to pass this info along as to my thoughts and see what others may think. ( Am I imagining things or not. )

Well if it ain't no longer broke and is working like you want than leave it alone, me thinks. One of the things I have tried that seems to work to improve ignition in some guns is to load with a pick in the vent and creating a clear fire channel into the main compressed charge. The pan flash won't have any trouble igniting the main charge through that length of clear vent channel any more than it does in a well designed and clear patent breech.

 

[Rifleman1776]

I would not have expected to see Swiss brand 3Fg powder dribble through a 1/16" touch hole.

My first thought exactly also. But, others have already replied with spot on good info. I particularly like the "if it ain't broke don't fix it".

 

[reddogge]

I've always used 2F in .50.

 

[EC121]

When I was shooting contests, I would plug the hole with one of those little dental brushes. It would let the air out and stop the powder. Then I would pick some priming in the hole at the line.

 

[Eric Krewson]

I have a Bill Large barreled rifle that has a huge touch hole, it will self prime a full pan with 3F, I load it with a toothpick in the hole to prevent powder loss. This rifles touch hole liner is screwed into the breech plug, my attempts to remove it have come up empty. Being a gift from a dying friend, damaging this rifle while trying to correct an oversized touch hole is not in the cards. Even with this huge touch hole this is the most accurate rifle I own.

Here is how the touch hole is screwed into the breech plug.

All my rifles have a 5/64" touch holes, they will drop a couple of grains of powder in the pan even with 2F, I have not found this to effect accuracy in any way, I do tilt the prime toward the touch hole after I load so a little 4F can run into the touch hole.

 

[Flint62Smoothie]

I too use 5/64" (0.078") sized touch holes and I barely ever notice any powdah dribbling out of the TH. Instant ignition works for me!

 

[Rob M.]

I have a Bill Large barreled rifle that has a huge touch hole, it will self prime a full pan with 3F, I load it with a toothpick in the hole to prevent powder loss. This rifles touch hole liner is screwed into the breech plug, my attempts to remove it have come up empty. Being a gift from a dying friend, damaging this rifle while trying to correct an oversized touch hole is not in the cards. Even with this huge touch hole this is the most accurate rifle I own.

Here is how the touch hole is screwed into the breech plug.

View attachment 275997

All my rifles have a 5/64" touch holes, they will drop a couple of grains of powder in the pan even with 2F, I have not found this to effect accuracy in any way, I do tilt the prime toward the touch hole after I load so a little 4F can run into the touch hole.

Very interesting . Ive seen all kinds of different T.H. types , positions and T.H. sizes . I prefer 5/64 myself and has served me well over the years . The late famous English gunbuilder Kit Ravenshear advocated an even larger T.H. size but I like 5/64 and I hear folks sometimes complain about it leaking a little powder with 3F during loading but I really like that size .

 

[Rob M.]

I too use 5/64" (0.078") sized touch holes and I barely ever notice any powdah dribbling out of the TH. Instant ignition works for me!

Me too bud !!

 

[M. De Land]

I have a Bill Large barreled rifle that has a huge touch hole, it will self prime a full pan with 3F, I load it with a toothpick in the hole to prevent powder loss. This rifles touch hole liner is screwed into the breech plug, my attempts to remove it have come up empty. Being a gift from a dying friend, damaging this rifle while trying to correct an oversized touch hole is not in the cards. Even with this huge touch hole this is the most accurate rifle I own.

Here is how the touch hole is screwed into the breech plug.

View attachment 275997

All my rifles have a 5/64" touch holes, they will drop a couple of grains of powder in the pan even with 2F, I have not found this to effect accuracy in any way, I do tilt the prime toward the touch hole after I load so a little 4F can run into the touch hole.

I build my own vents out of A-2 high chrome tool steel left in the annealed state and start with an .0625 vent hole. My SMR was made from a TOTW kit using a GM barrel and Chambers/Siler Deluxe lock. It is very reliable and seems instantaneous to fire with this size vent hole.
My general feeling is to stay with the smallest vent diameter that affords reliable and fast ignition without any interior funneling. The vents I make are clocked to index interior profile of the vent which is the same as the radius of the barrels groove diameter for a flush fit so there are no corners or pockets of the vent liner and it's threaded hole seat to catch fouling.
I don't care for interior coning at all (White Lighting vents) and much prefer to vector the pan flash inward ( exterior coning) rather than the breech pressure outward.
Time and use will tell the story but I feel this will extend vent life as well as increase main charge burn efficiency.
It seems to work much like a fresh nipple does in retaining chamber pressure that when worn out will often blow the hammer back to half cock and then accuracy begins to fall off.

 

[Eric Krewson]

All of my rifles have white lightning liners in them, I don't see a down side in using them, just guessing, I suspect 90% or more of the people building rifles use them.

All care about are the groups I shoot and the deer I kill, I don't concern myself about the technical aspects of the load, just how well it performs. Every one of the rifles I have built will shoot tight a cloverleaf at 50 yards which is also the extent of my 76-year-old eyes and lining up iron sights. I have shot a 1" 100-yard group with the first rifle I built but that was on a day when the stars must have aligned perfectly, the wind was calm, and the sun was just in the right position to un-blur my rear sight just enough to let me line things up.

It is a 50-mile drive to the 100-yard public range and a 30-yard walk to the 50-yard range I have at my house so I do all my shooting at 50 yards.

My 50 yard range and the sand filled bullet trap, the black box on the left. I over did it and made it 48"X36", 3 feet of sand is way too much, this amounts to shoveling a yard and a half of wet sand.

 

[French Colonial]

I have never seen a white lightning liner than was eroded enough to replace due to firing. The liner in my Jaeger is going on 40 years old.
I am sure some have screwed them up to the point of needing replaced but that is different.

If any one has actually shot one out I would be interested to know how many shots it took.

Edit, all of mine are 1/16 inch and ignite whatever powder I happen to put in the barrel.

 

[M. De Land]

All of my rifles have white lightning liners in them, I don't see a down side in using them, just guessing, I suspect 90% or more of the people building rifles use them.

All care about are the groups I shoot and the deer I kill, I don't concern myself about the technical aspects of the load, just how well it performs. Every one of the rifles I have built will shoot tight a cloverleaf at 50 yards which is also the extent of my 76-year-old eyes and lining up iron sights. I have shot a 1" 100-yard group with the first rifle I built but that was on a day when the stars must have aligned perfectly, the wind was calm, and the sun was just in the right position to un-blur my rear sight just enough to let me line things up.

It is a 50-mile drive to the 100-yard public range and a 30-yard walk to the 50-yard range I have at my house so I do all my shooting at 50 yards.

My 50 yard range and the sand filled bullet trap, the black box on the left. I over did it and made it 48"X36", 3 feet of sand is way too much, this amounts to shoveling a yard and a half of wet sand.

View attachment 276455

No one will deny WL liners help ignition in poorly designed flint guns but they do exhaust chamber pressure off the main charge like a header on a car engine creating/ vectoring a blow torch effect which is annoying and potentially dangerous to any one shooting along side them. I've been burned more than once by their use next to me and have found them quite unnecessary to good ignition in well built flint guns .
They just are not necessary to good ignition in well engineered flint guns and in my opinion are a nuisance on a firing line .
If the reasoning for their existence is to lesson main charge distance from pan flash ignition travel, why not reduce the distance from the outside and vector the pan flash inward by exterior conning rather than aiding main charge pressure exhausting outward ? It seems to have the same effect on the ones I've been making but it will take time and use to prove it of equal value.
My guess is WL liners probably make sense on a hunting rifle as one wants every advantage to insure ignition in less than perfect conditions and there is usually no one to be burned by vent exhaust off to the side but liners (except for burned out vent repair) were not around in the Golden Era of flint gun use but I suspect coning of the interior of the vent through the barrel wall was.

 

[M. De Land]

All of my rifles have white lightning liners in them, I don't see a down side in using them, just guessing, I suspect 90% or more of the people building rifles use them.

All care about are the groups I shoot and the deer I kill, I don't concern myself about the technical aspects of the load, just how well it performs. Every one of the rifles I have built will shoot tight a cloverleaf at 50 yards which is also the extent of my 76-year-old eyes and lining up iron sights. I have shot a 1" 100-yard group with the first rifle I built but that was on a day when the stars must have aligned perfectly, the wind was calm, and the sun was just in the right position to un-blur my rear sight just enough to let me line things up.

It is a 50-mile drive to the 100-yard public range and a 30-yard walk to the 50-yard range I have at my house so I do all my shooting at 50 yards.

My 50 yard range and the sand filled bullet trap, the black box on the left. I over did it and made it 48"X36", 3 feet of sand is way too much, this amounts to shoveling a yard and a half of wet sand.

View attachment 276455

Eric, I wonder how a WL liner would work threaded ass end to ?

 

[French Colonial]

No one will deny WL liners help ignition in poorly designed flint guns but they do exhaust chamber pressure off the main charge like a header on a car engine creating/ vectoring a blow torch effect which is annoying and potentially dangerous to any one shooting along side them. I've been burned more than once by their use next to me and have found them quite unnecessary to good ignition in well built flint guns .
They just are not necessary to good ignition in well engineered flint guns and in my opinion are a nuisance on a firing line .
If the reasoning for their existence is to lesson main charge distance from pan flash ignition travel, why not reduce the distance from the outside and vector the pan flash inward by exterior conning rather than aiding main charge pressure exhausting outward ? It seems to have the same effect on the ones I've been making but it will take time and use to prove it of equal value.
My guess is WL liners probably make sense on a hunting rifle as one wants every advantage to insure ignition in less than perfect conditions and there is usually no one to be burned by vent exhaust off to the side but liners (except for burned out vent repair) were not around in the Golden Era of flint gun use but I suspect coning of the interior of the vent through the barrel wall was.

If white lightning liners help ignition in poorly designed flint guns...... Do they NOT help ignition in well designed flint guns?

Obviously you do not like them, I have used them for decades and do like them and see no reason to have one coned on the outside for no other reason than it is butt ugly to me.

 

[M. De Land]

If white lightning liners help ignition in poorly designed flint guns...... Do they NOT help ignition in well designed flint guns?

Obviously you do not like them, I have used them for decades and do like them and see no reason to have one coned on the outside for no other reason than it is butt ugly to me.

Isn't choice and contrary opinion wonderful concepts ?

 

[waksupi]

I don't know how people get decent accuracy after enlarging a vent. I have never enlarged one when building, and am generally replacing them when they get burned out to the point people recommend drilling them out to, as accuracy is starting to fall off by that time.