I have a cannon I built. The “tube” is 8” OD and about 8’ long. Very simple, it is welded shut at the breech, open at the muzzle. Touch hole is much like a civil war cannon, being the only opening at the breech. Looks kind of like a WW1 Howitzer.

Anyway, to shoot it (the tube only has a 1/4” wall) I use oxygen and acetylene. A basic welding outfit.

I put a plastic bag over the muzzle, tape it in place. Then I set the gas regulators to equal pressures and use a welding tip on the torch handle. Open both torch valves and put the tip in the touch hole. Count to 10 or 15 or 20. Remove torch, spark it to light it and then sweep lit torch over touch hole. Boom.

No projectile. Potentially Big Bang.

Vary time in touch hole to vary result.

If the one in the pic is a deactivated weapon, drilling a touch hole shouldn’t change anything. The Law can get quite excited about “Reactivating” a class 3 weapon.

In addition, should the local constabulary become involved, a gas gun is much less likely to raise eyebrows.

Brownells does not sell tritium sites for it , and stippling would break the bank so no.