Does anyone use nitromethane/methanol model fuel as a propellant?

Lead melts at about 600 degrees centigrade, so you can melt it fine in a stainless steel saucepan. DO NOT use an aluminium pan, as this has a similar melting point to that of lead, so the pan will melt.

You'll also need a high melting point grease to stop the lead from sticking to the mold. There ...

I think an oxy-acetylene powered combustion gun would beat almost all pneumatics , but building a safe one would be next to impossible. And you'd need a license to store acetylene over here

I call mine an air cannon. I don't really launch potatoes as the barrel is either 20mm or 15mm depending which barrel I have fitted.

Ball valves can take higher pressures and are better if you want to shoot stuff at 200+ psi
They work fine and can be made to open faster by using a spring to open them.

Obviously you'll be using copper pipe or something stronger at these pressures

In the UK we're only allowed certain types of firearm and you have to have a decent reason to own one. However, I don't think that there are any restrictions on owning a silencer. I guess the government thinks that if we can't have guns, there's no point in banning silencers.

However, you need a ...

The ammo slightly flattened on impact with a steel sheet, after it had punched through a piece of 3/4 inch plywood that I was using as a target. However, I can recast the shot, which saves on lead.

I think you can buy these molds in some gun stores. I picked mine up from a car boot sale after ...

I've recently come into possession of a musket ball mold and can make lead shot for my air cannon. The ammo is 20mm in diameter and fits perfectly into my barrel.

The ammo weighs in at roughly 45g. However, due to some lead casting problems, the shot is actually hollow and should therefore weigh ...