Touch hole wall thickness

[flintriflesmith]

Touch hole erosion was obviously an issue in the period and it was addressed in top of the line European (and a handfull of American) guns by the use of gold or platinum.
I have seen a few originals where those precious metals were plucked out and was surprised to see that they were not threaded at all! They were about the thickness of a dime or less and just inlaid over a drilled touch hole (about 3/16 inch in diameter) to form an outer wall to the chamber.
When I say inlaid I mean just that--the erosion proof metal was trapped in place the same way a signature plate would be inlaid in the top of a rifle barrel. I never bothered to measure any of them but they were larger than seemed necessary and I always wondered if the smiths were counting on the lock to help hold them in place!
I know of one new rifle made in the mid-1960s that had this kind of gold touch hole and the shooter managed to blow it out by loading multiple charges during a penetration test.
Gary

[Acer Saccharum]

Gary, I had always assumed there was a bushing in the hole. From what you're saying, it's just a disk with a hole laid over the enlarged touch hole...that is, laid in a pocket, edges undercut. Wow.

Oi 'ave this lit'l disk stuck in me 'ead. Only 'urts on rainy days.

[bgf]

Gary, I had always assumed there was a bushing in the hole. From what you're saying, it's just a disk with a hole laid over the enlarged touch hole...that is, laid in a pocket, edges undercut. Wow.

Oi 'ave this lit'l disk stuck in me 'ead. Only 'urts on rainy days.

I think that is one period correct detail I'll skip !

[JB2]

Pletch, I thought of something 'after' I posted above.  I think you'll need a complete gun to do this test, right?  The one with the .32 barrel is nowhere near complete.   Everything else I have is percussin.  uh, sorry?

[Larry Pletcher]

Pletch, I thought of something 'after' I posted above.  I think you'll need a complete gun to do this test, right?  The one with the .32 barrel is nowhere near complete.   Everything else I have is percussin.  uh, sorry?

Not a problem.  Steve is finished up a flint half stock that will be the test rifle.  It is nothing special. After the testing, it will be a deer gun if I can hold it up.  (That is becoming more and more of a problem.)
Regards,
Pletch

[Dan Fruth]

The thing that concerns me is when the vent burns out...what then?? The owner of the rifle will have to put in a liner of larger diameter, and if the vent was placed toward the top of the side flat, that will cause some problems that I personally don't want to saddle the owner of one of my guns with. I think I'm going to stick with coned bushings that seldom burn out, and are simple to repair when they do.