Eroded Vent

[Dphariss]

This vent was still about .063 with a guage (drill shank) but is still out of shape with sharp cuts in it.
Don't know how many rounds. I don't bother counting.


Dan

[greybeard]

Hello Dan I can see that the hole is a bit jaged and have no idea why but will be the first one to ask the stupid question,..
What kind of gun is it???
Bob

[Dphariss]

Hello Dan I can see that the hole is a bit jaged and have no idea why but will be the first one to ask the stupid question,..
What kind of gun is it???
Bob

Its my 50 cal wender.
Nor has a metal pick ever been used on it.

Dan

[jimc2]

Dan what is the liner made of??

[Jerry V Lape]

Hard to tell from photo, but it appears your exterior chamfer made a knife edge with your interior chamfer - sort of making a knife edge.  I think this was a good thing from aspect of quick ignition but probably not great for durablilty.  I am not an expert at this, but when I put my vent liner in I decided to leave a straight section between the interior and exterior chamfers for fear of making it easy to damage the vent edges or for gas cutting to damage it easily. 

[D. Taylor Sapergia]

Dan, I don't think you need to worry about your vent for a while...when it gets out to more than .070" I'd likely replace it.  I don't worry even when the pan gets a few powder kernels in the pan during loading with the frizzen closed.  Accuracy likely diminishes though.

[T*O*F]

Why isn't the liner concentric with the hole underneath it?  Looks like it was relocated backwards.

[D. Taylor Sapergia]

...awesome rifle Dan...always like seeing pics of it.

[Dphariss]

Thanks  Taylor.


The liner.
The liner is 303 (or maybe 304 since I sometimes had some of this around if 303 was not available) stainless. 303 is the same as WL are made from IIRC. I built that breech in 1993 but did not get the rifle stocked until about 6 years ago. Its been replaced with one with a proper chamfer externally. I was going to take pics of the whole thing but as usual I forgot once I started.
 It was not shouldered at the exterior but was supposed to be at the interior. THese work OK if seated at the bottom of the hole. I used a piece a 3/8 rod to make its replacement its seated at both the bottom of the hole and the top.
This liner had an internal and a slight external cone. The one in the other barrel, which I replaces a few years ago for a reason I don't recall, to get rid of the external cone I think, worked no differently than this one. But the external cone did make the erosion harder to see.
This is not a very hard stainless nor can it be hardened. It machines very well and the specs say it has excellent corrosion resistance.
It had been shot some but as I stated I never keep track. Its the only one I have ever noted this occurring in. I would think its some flaw in the rod it was made from.
I thought the erosion was interesting so I posted the photo here.

Dan

[DaveP (UK)]

I hope no one minds if I ask a newbie question here - How important is it to use a vent liner anyway? or What sort of service life could one expect from a simple drill hole in a modern barrel?

I do realise that retro fitting is likely to be a more demanding task than installation when building, and I'm almost certain to take the latter option, but I'm curious by nature 

[bob in the woods]

I no longer install vent liners as standard procedure on new guns. I do chamfer the vent from inside a bit, but that is all.  My .40 cal has about 1000 rounds through it and it is starting to get enlarged but is still serviceable. My 10 bore is doing better. My target rifle has a liner [ 2nd liner ]  but it has thousands of rounds through it. Ist was stainless steel , this one now is beryllium copper.  My main concern is reliability.
If the gun goes boom, I'm happy. Especially when bear hunting.  Some think anything more than 1/16th inch is too big, while mine average 5/64ths and work fine. My own opinion is that most original longrifles did not have liners when new.  Will your gun work without a liner? Absolutely.  Will it be better with a liner?  Perhaps. 

[Dphariss]

I hope no one minds if I ask a newbie question here - How important is it to use a vent liner anyway? or What sort of service life could one expect from a simple drill hole in a modern barrel?

I do realise that retro fitting is likely to be a more demanding task than installation when building, and I'm almost certain to take the latter option, but I'm curious by nature 

When I started  shooting FL the standard plain vent was 3/32". Not particularly reliable and require loading with a closed frizzen or a plug in the vent. If the gun is carried in a vehicle powder will run out the vent under the vibration even with a .065-.070 vent unless plugged. These also pass powder when loading if FFF is used.
Smaller simple drilled vents are not that reliable.
The English were the masters of the Flintlock. Their locks and vents were without parallel. They used liners very much like the WL.



Its simply not possible for a 1/16 straight drilled vent in a barrel with a .250-.300 wall to be as reliable as this.



I like flintlocks. I like longrifles. The vent being at odds with what may or may not have been used does not worry me. For one a great many of surviving flintlock rifles have been converted twice, once to percussion and then back to flint. So knowing what the original pan was like, what the cock was, how the frizzen looked and what the vent really was is all lost. Most are now generalities that are successful at some level.

What people have to remember about a vent is this. The vent works off radiant heat. There is no flash of fire into the vent. Its impossible. So unless there is powder in the simple vent, which will occur in most cases if the gun is carried around as in hunting, the main charge is .250-.300" from the pan. A vent liner that puts the main charge with .020-.040 of the pan EVERY TIME is more consistent.
The British jumped through a lot of hoops to get the flintlock to where is was by about 1800-1815. Some of the stuff they came up with was snake oil but Nock's breech works as Manton's recessed breech did as well. Having the added benefit that it allowed doubles to be 1/2" or more narrower at the breech.

A flash in the pan is an inconvenience, stalking some animal for a mile and a half over hill and dale. perhaps running to get to a choke point. Maybe low crawling to get close enough. Then having the rifle flash? Very frustrating. People who hunt in the east don't really understand spot and stalk as many do it out here. I scope areas from 2-3 miles away then drive as close as I think is necessary to get to whatever property line then taking a route that will hopefully get me within 100-120 yards.



Dan

[D. Taylor Sapergia]

Replacing liners because of this gas cutting erosion is just part of the routine maintanance of a flint gun.  I used Ampco liners @ 1/4 x 28tpi for years until the white Lightning came along.  Both improve reliability and speed of ignition, over a simple bored parallel vent.  It would be pretty hard to argue otherwise.  Authentic? - don't care.  There's few things more frustrating than a flintlock rifle that lets you down over and over again.

[Acer Saccharum]

I, too, like the internal cone that the vent liner offers. On my last two rifles, I used Tom Snyder's internal coning tools. I expect that the vent will erode faster than a stainless liner. But when it does wear, I can install a stainless liner.

I suspect that 304 will erode quicker than 303, but it's soooo much easier to machine. I s'pose one could play around with a platinum lined touch hole. But I probably won't wear a gun out enough to go thru that trouble.

Thanks for the interesting topic, Dan.

[Bob Roller]

I don't think any long rifles in our Museum of Art has a vent liner. I'm thinking
that the liners were a London idea when major improvements in flintlocks stalled
use of percussion or detonating locks for quite a while. The small hole in the side
of the barrel gives rise to the derogatory remarks made about flintlocks today.
My own flinter went off like a caplock and with a decent flint,it never misfired.
That double barreled flintlock shows a woderful example of a fast fire system that
is as reliable as can be made with an external ignition system.
Like Taylor,I don't care about authenticity in this area. I much prefer the abrupt ignition of the barrel charge
than the hiss of a fuse thru a tiny hole that is probably at the bottom of the pan.   
Bob Roller

[bob in the woods]

With a 5/64 drill bit, and internal coning bit, I have not had any problems at all. I have enough faith in my rifle and smoothbore to hunt bears and moose with them. I believe that the main advantage of a liner is the hopefully better wear characteristics of the material. Also...we really should discuss what kind of liner.
When needed, I go to a Chambers White Lighting liner. He has different sizes to cover various barrels.
In my day I have seen some liners that caused more trouble than they were worth. I had a gun years ago that had a liner that collected crud like a magnet ! 

[Vomitus]

  As a shooter,I really like the idea of the liner getting the prime closer to the charge.All my guns and rifles have a "White Lightning" liner now.

[Dphariss]

I, too, like the internal cone that the vent liner offers. On my last two rifles, I used Tom Snyder's internal coning tools. I expect that the vent will erode faster than a stainless liner. But when it does wear, I can install a stainless liner.

I suspect that 304 will erode quicker than 303, but it's soooo much easier to machine. I s'pose one could play around with a platinum lined touch hole. But I probably won't wear a gun out enough to go thru that trouble.

Thanks for the interesting topic, Dan.

I don't know if there is a lot of difference though 304 is supposed to be tougher to machine I can't tell the difference in machining or drilling or tapping. 304 might be better for erosion resistance. Don't really know.

Dan

[LH]

As Dan pointed out,  there are some real good performance related reasons to use a chamber and a vent liner.  For the past 20 years,  I've made my liners out of 5/16" ss set screws.  Turn the closed end flat, center drill, drill through with a 1/16" or slightly smaller drill,  cone the outside with a 5/16" ball end bit,  then cut a screw slot with a small cutoff wheel just to the depth of the outer cone.  Turn it around and cone the inside with a 7/32" ball end bit leaving the thickness of the vent hole web at about .020". Cut to whatever length you need and screw it in.  I wrap my liner with Teflon and remove it to clean the barrel with a flush tube. I replace when they get up to .070.   I also chamber my guns by drilling into the face of the breechplug to a depth of about 3/8", then drill the liner hole through the barrel into the side of the breechplug to mate up with the hole in the front end.   Use a ball end bit to eliminate the shelf where the two holes meet, and do not drill past the back end of the liner hole. Cone the front end hole up to bore diameter.  I use the same drill for the chamber as I do for the liner hole.  I think its an "I" drill.  .277" iirc.  Larger did hot work well for me.   This system is the one I have used because it works.  Fast ignition,  and seldom have a flash or misfire.  This past weekend I shot in the Alabama territorials and shot five 20 shot rifle aggs.  No misfires, no flashes, and only a couple of barely noticeable slowfires.