Outside-coned flash hole

[frogwalking]

A few months ago, I was having problems with lock-barrel-breechplug relationship on a kit I was building.  Someone told me of a method of making a coning tool from a file to cut a cone on the outside of the barrel to solve the slow ignition problem that plagues direct drilled flash holes.  I made the tool on the right of the attached photo.    It worked beautifully, but the rifle still suffered from inconsistent, slow ignition and frequent flash-in-the-pan. occurances.  The barrel is a  Rice, B- weight .45 caliber and is proving to posess fine accuracy potential.   I was thinking of making a new tool with a wider angle to see if that would improve the ignition.  While at Lowe's, buying material for a home project, I spied the moto-tool bit shown on the left of the photo.  It chattered in my moto-tool, but worked just dandy in my Chinese drill press.  I verified that I had not opened the interior flash hole by checking it to verify that a no. 50 drill bit would not pass through.  The ignition is greatly improved, with good reliability and reasonable speed.  I am writing this incase anyone else is having this issue, and offer the cone shaped bit from Lowes as an alternative to making your own. (Assuming this is right for your barrel thickness.)

[bob in the woods]

I'm glad that you seem to have solved your ignition problems, but I would not have coned that aggressively from the outside.   Does the cone interfere with the seal of the pan against the barrel ?  There is a simple tool available that lets you cone the barrel from the inside if you want to. That would be my first choice.  I think Caywood guns have an outside cone, so I guess it's a personal choice.

[Dennis Glazener]

Personally I would not fool with an outside coned flash hole from the standpoint of performance and appearance.

I used a piece of 1/16" oil hardening drill rod, heated it red and flattened it in a Christmas tree shape (with the 1/16" shaft being at the top). Then used a file to put a cutting edge on both sides then cut it short enough to go inside the .54 caliber breech and slip the 1/16" shank into the flash home. Used my electric drill to spin the cutter slowly while pulling the cone shaped cutter toward the outside of the barrel. It worked as good for me as a white lightning liner. Suspect you could also do this with a 50 caliber but probably no smaller due to how short you would need to make the cutter & shank.

Somewhere on ALR there is a topic on this, I forget who came up with the idea, not me but it did work well for me. I think the original person used a small finish nail and case hardened the cutter.
Dennis

[Elnathan]

Somewhere on ALR there is a topic on this, I forget who came up with the idea, not me but it did work well for me. I think the original person used a small finish nail and case hardened the cutter.
Dennis

Chris Immel, I believe.

[frogwalking]

The outside coned flash hole was not my first choice either, but the swamped barrel was inlet, as was the lock, so they were fixed in location.  The white lightning flash hole liner I planned on using would have required a sizeable groove in the breech plug.  That may have worked, but I was not comfortable with it.  I studied on the matter for quite a while before settling on this fix.  I was following (the best I could) an article by Jack Brooks from the Muzzle Blasts.  The largest part of the cone on the outside of the barrel is only about 9/64  inch, so no, it does not compromise the lock to barrel seal.  I don't think it looks any worse than a shiny stainless steel disc in a brown barrel around the flash hole, and the best part is that it works!

Note:  It may have been possible for me to move the barrel back a tad to allow the use of the white lightnin hole liner, but I didn't realize the problem until the flared tang was inlet, and the barrel pinned.  I think this was what they charitably call a learning opportunity.   

[whitebear]

On my first flintlock rifle I drilled a 3/32 flash hole following advice in the back of the Dixie catalog (remember this was still the dark ages of rifle building the ones who knew weren't divulging any secrets and there was no handy internet with the ALRA or Goggle) and counter drilled on the outside to a larger size (this was in 1977 so I don't remember what size) and got great ignition and the flash hole didn't look all that much out of proportion.

[JCKelly]

I have owned two otherwise finely made flint long-guns with outside coned touchholes.

So far as I am aware no one, no one, no one at all in the 18th century produced guns with outside coned touch holes. These guys made guns for people whose lives depended on them, real important that they actually worked. Think there might have been a connection there.

I did not like my outside coned guns. At all.

Coning from the inside sounds like an idea, as do various touch hole liners coned from inside (you might want to make your own liner from actual 304 or 309 bar, rather than that chancy stuff called 303, but that is just my P.I.T.A. metallurgist view).

I believe there has been work done by a well-respected gentleman showing no ignition speed disadvantage to outside coned touch holes. I do respect his work.

Nevertheless, me I just couldn't get the thing to go BOOM without religiously picking the vent before, during and after loading, maybe on alternate Tuesdays as well. Reaming out the touch hole helps, of course. As does loading with FFFg rather than FFg.

Innovation is a wonderful thing. Maybe not so much when it comes to muzzle loading rifle design.

[JV Puleo]

I have a Charles Grierson officer's musket made (if I remember correctly) in the latter half of 1796 or the first half of 1797 (dateable because it falls between the dates he went into business and the date he received a Royal Warrant). It is nearly unfired. Because it has no gold or platinum liner, I wondered if anything had been done to the touch hole. It is definitely tapered from the outside in and I was able to measure it using a set of numbered drill bits... from one that would just enter the breech, to one that matched the diameter at the pan. I think I came up with something very close to a 00 or 000 taper pin dimension.

[Dphariss]

People that want to "fix" a vent need to look at the English flintlocks. The high end ones. They are all flat faced. Outside cones have to be cleaned to make the reliable. Fouling in the external cone is a cause of problems if they are very deep at all.



This is the final evolution of the flintlock.
These high end English makers simply did not make guns that did not work. The made guns for Royalty and Peers and one simply does not sell a gun to HRH that does not work. Period. Its not going to happen.

Dan

[Larry Pletcher]

In the February 2000 issue of Muzzle Blasts I reported on a test of straight cylinder vents.  I covered diameters from .052" to over .090" . when I timed  a 1/16" vent I used a countersink to add a mild exterior cone.  I timed 20 trials and found the average.  With the 1/16" (.0625) vent, I reported an average of .0440 seconds.  The exterior cone averaged .0406 seconds. The high-low variation was slightly smaller with the exterior vent as well.  A straight hole diameter of .070" averaged .0408 seconds.  These tests were done with Goex 4fg as priming.  I have since tested vent liners that were quicker, using Swiss Null B for prime.

Dan's comment about cleaning did not show up in my tests because I cleaned very carefully in my tests to avoid fouling as a variable.  I don't currently shoot an exterior cone, so I can't comment on this type of vent on a rifle.  I am about to do an experiment on a exterior cone with a shape like a trumpet bell.  The idea came from a fluid dynamics guy.

Before my web site was hacked, this article was available on line.  If you save your MuzzleBlasts, it's on p. 11 of the Feb 2000 issue.

Regards,
Pletch

[Dphariss]

I have a Charles Grierson officer's musket made (if I remember correctly) in the latter half of 1796 or the first half of 1797 (dateable because it falls between the dates he went into business and the date he received a Royal Warrant). It is nearly unfired. Because it has no gold or platinum liner, I wondered if anything had been done to the touch hole. It is definitely tapered from the outside in and I was able to measure it using a set of numbered drill bits... from one that would just enter the breech, to one that matched the diameter at the pan. I think I came up with something very close to a 00 or 000 taper pin dimension.

A shallow taper is not the same as a cone.
This also sounds like a pretty large vent for anything but a Musket.
.100" +.
Dan

[little joe]

I have coned several barrels from the outside. My expearances are every where from excellent to  not so good. The last two rifles, same bbl. diameter, sam brand and model of lock first gun excellent, and the other one average/ I think gun no. 2 is going to get a white lightening. My conclusion is try it and if it don,t work, put a liner in it. Going to shoot a fresh one this morning and we will see.

[Acer Saccharum]

I had tried a 1/16 straight, and gun went off once. I opened it to .078 straight, and it was misery at best. Then I coned the touch hole from the inside, and now I'm happy.

I used the inside cone tools by Tom Snyder ('Snyder' on ALR)

I have used the 'white lightnin' liners by Jim Chambers and really like them as well. I believe they are also available in 4140 steel from Chambers, which browns nicely with the rest of the bbl.