Touch hole too far back - repairable?

[Jaepheth]

.44 Caliber flintlock.

Has a long firing delay (~half second)

I'm pretty sure it's because the touch hole is drilled at an angle.

My question is, what is the correct way to repair this (if any)? Can I drill a large hole, slightly offset forward (centered over the breech face), and install a liner? Maybe file a larger channel for the flash pan to keep the touch hole accessible? The idea being to create a "pocket" in the breech face.

Or can I drill a larger angled hole for a liner, keeping the existing center, but creating a better channel for the priming charge?

 

[illuveatar]

I'm not sure an angled touch hole would be cause for such a delay but others here may be more knowledgable

A little more info might help verify the cause of the delay. What kind of priming powder are you using ? And what are you using as your main charge ? And what is the diameter of your touch hole ? Is it consistently having a hang fire ? Does it also fail to fire quite often ?

If you install a liner that is farther forward then it may not line up with the priming pan.

I would consider removing the breech plug and investigating the inside of the barrel.

 

[Jaepheth]

The delay is quite consistent

Was shooting 35 grains FFF, also primed with FFF

touch hole seems to be around 3/32 or 2.5mm diameter

 

[paulab]

My .36 flintlock had exactly the same problem. Drilling out the touch hole didn't help. What finally cured the problem? I removed the breechplug, drilled a 1/4 inch hole in the center of it until it was just past where the touch hole would be when drilled at the correct 90 degrees. I made it a patent breech. Then I plugged up the original angled touch hole in the barrel wall and the breechplug by threading the holes and screwing in small screws. File or grind off any part of the screw that protrudes. Re-install breechplug. The last thing I did was to install a touch hole liner. Ignition now is as fast as any of my other flintlocks. HUGE IMPROVEMENT!. Hope this helps. Cheers Paul

 

[thatoneguy82]

I did much the same thing on a Dixie Tennessee mtn rifle I converted to flint. The factory hole was rear and high in the pan of the L&R RPL lock. I threaded a piece of cold rolled and turned a shoulder on it and chamfered the original hole, plugged it and filed flat then spotted the touch hole in the proper location. With the new vent liner installed it acts as a lock screw and prevents the plug from ever moving. Be careful that the material you use as a plug isn't much harder than your barrel, otherwise your drill even in a drill press could wander into the solfter barrel material and away from the plug.

 

[Col. Batguano]

:thumbsup: Good point. Keep as little of the bit exposed out of the drill press chuck as possible, (to help keep it from bending during drilling) and make a good strong center punch to locate and start your drill with. I've run in to the same thing when trying to drill through taps I've broken off and couldn't get out.

 

[galamb]

Here is a couple of diagrams to illustrate what is being tossed around here.

It's called a chambered breech. It's also a method to get the touch hole where it needs to be if the breech plug extends too far forward to get things aligned properly.

Although this is a percussion breech, it could just as easily be a flint.

Another diagram - same idea - your result, with the angled flash channel would be like a combination of these two diagrams.

Every rifle I build has a chambered/patent breech, so very familiar with the style. When drilling the chamber (into) the plug you do want to keep it below bore size.

On commercial versions it's generally somewhere around 32 cal in size. I have found that if you go the next caliber below bore size you never have powder bridging issues (or maybe that's just coincidence).

So if my bore is 50 cal (.500"), I will bore the chamber to 45 cal (.450 or .440).

 

[jerrywh]

Recess the face of the breach plug.

 

[Vaino]

Your drawings explain it well. Many percussions have what you've drawn or something vey similar.

Asre the flint setup.... what's the advantage? Seems a lot more complicated than a flat faced breecbplug w/ no reason to do it. Or is it only for a relocation of the TH?.....Fred