can a straight drilled touch hole be as fast as one with a liner ?

[Pukka Bundook]

I'm with Bob in the woods, and like a 5/64" touchhole on anything.
Never could take to a tiny touchhole.
My short and long matchlocks I coned on the inside, and thay both go off like greased lightning.
If I do install a liner, I make them of 3/8" stainless, and a normal touchhole liner will pretty well fit inside them.
3/8 won't work on all barrels, but works on a great many.
here's one on a .44 cal homemade barrel.
Never liked the store bought liners, apart from Jim's white lightnin.




yes, gun had gone rusty living outside!
Was in for a clean.

[foresterdj]

Sooo, obviously simple drilled through flash holes worked back then, and now.  And there are anecdotal observations that a drilled hole is just as fast, though the timed studies would seem to show that as not the case, but in most cases all options are too fast for human visual observation. Some have proposed coning the actual barrel from inside (or I think someone suggested outside) to accomplish the same thing (moving the charge closer to the flash).

My question is, might the coning of the touchhole compromise your ability to drill and tap for a touch hole liner later, if desired?  Or can liners be acquired in sizes large enough to still work?

[Pukka Bundook]

I'd say most times an inside coned touchhole  would not be a problem at all if a liner were to be fitted.
I think what folks are saying here, is a coned barrel is as fast as a liner, because mechanically it is exactly the same. 
A straight touchole can be iffy.
We read lots of old gunmaker accounts of "New touchhole, fresh pierced".

[Marvin S]

Vent holes need to be placed right close to the breech plug seat. So close in fact that you need to notch the face of the breech plug. If the hole is drilled forward of the face of the breech plug it will be slower ignition.  Like others have pointed out. It is the hollowed feature on inside of the touch hole liner that makes it more reliable.  A regular touch hole can can be coned out a bit with a ball burr.  This gets the powder charge a little bit closer to the flash pan.  I have also coned the hole on the outside of the barrel this works just as well.   I think installing a touch hole liner should wait until after your touch hole gets rusted out.

I’m in the opposite camp. I would rather have vent placed well ahead of breech face to ensure fresh powder ahead and behind touch hole to ensure reliable ignition. Not powder ahead and fouling behind. I sure can’t see how ignition would be slower. Maybe you could explain?

[Daryl]

 ;)I'm thinking a straight drilled hole, if large enough, could be a fast as a good liner.  To be that large though, there would be a horrendous
amount to flame and pressure lost out the gigantic vent hole - I'm thinking 3/16" might work, speed wise.

[smylee grouch]

I'm thinking a straight drilled hole with no cone inside or outside will work better on thin walled barrels better than on heavy thick walled barrels as others have spoken of. I don't think a straight drilled barrel is going to be as fast as a good and properly installed white lightning. As per Pletches tests. JMHO

[oldtravler61]

  Daryl didn't someone do a speed test on the difference between touch hole size..?    Seems I remember something to that effect.. IIRC . The article was in Muzzle Blasts and the Bevel brother's did the test or reported it.   Or more than likely I'm crazy....

[BrianS]

https://www.blackpowdermag.com/touch-hole-ignition-timing/

https://www.blackpowdermag.com/pan-vent-experiments-an-introduction/

https://www.blackpowdermag.com/category/articles/lock-timing/