Swivel Gun Touch Hole Size

[Not English]

I've recently succumbed to the "big gun" bug and purchased a 1" bore swivel gun. It needs to have the touch hole drilled. Can anyone advise me of a touch hole diameter  to start? I do not plan on using fuse, but do plan on 3f for priming and "slow fuse" for ignition and priming.

Thanks in advance,
Dave

Moderator, please feel free to move where ever you think it's appropriate. I realize it's not really longrifle related.

[Daryl]

1/16" inch or .0625" works for me.
"It needs to have the touch hole drilled"
Is this a "Made in India Gun", per chance?

[Hungry Horse]

 On the little 1 1/4” bore deck gun I had I made a touch hole liner out of a piece of stainless allthread in case the touch hole burned out, and I had to repair it. It never burned out, and I doubt the guy I sold it to has had to replace it.

  Hungry Horse

[D. Taylor Sapergia]

NE: start with a 1/16" drill bit.  Try to fire the gun.  If it fails to fire, or is super slow, enlarge it by 1/64" at a time until you get reliable ignition.  Don't worry about instant ignition, just reliable fire.  You may have to go as high as 1/8" which is the size of some original Brown Bess muskets I've examined.

[Daryl]

Didn't think about it at the time, but if solid walled, the vent hole will be long & slow ignition.
Making a vent liner would be a good idea, that way, it can be hollowed out on the inside.
Note that these big bores develop VERY low pressure with even elephant-sized loads of 12 to 16 drams.
After all, it is a 4 bore, more or less.

12drams = 328 gr.
16drams = 437 gr.

[bob in the woods]

By a swivel gun, I'm assuming it's much like a small cannon.  Mine has a touch hole on the top , located about 3/ 16th's " ahead of the breach face. The touch hole is 5 / 64ths " and there is an oval surround of brass silver soldered to the barrel. This brass piece is counter bored and the concave area of about 1 / 4 in in diameter goes right down and actually into the barrel a small bit.
This allows a priming of powder to be used , without weakening the touch hole walls .  The ignition is quick and reliable with the touch of the match cord. 

[Not English]

Hey all, Thanks for all the helpful information. Daryl, It's not a "Made in India". It was actually cast By Manitowoc Grey Iron. It's a small cannon on a naval carriage. It has a cone cast into the touch hole. The touch hole has not been drilled through the the barrel liner. I plan on fabbing a monkey tail and fork so I can mount it on a post. The fellow club member I bought it from has offered powder and instructional help. I don't think he has ever fired it because  he said it was just sitting in the garage and collecting dust. and could use the space. He's got 3 other cannon that I know of and several muzzleloaders as well.

Dave

[Daryl]

If the vent isn't drilled, he hasn't fired it. Mounting it on a post would be cool!