lol, truely quotable!

Dr. Nick: Inflammable means flammable? What a country!

I love how TV fallacy has warped our sense of what really happens.

first of all, a cylendar of acelaine will have a bullet rating of at least 10, you can shoot it and the bullet from a 9mm and the bullet will vapourize. If you shoot the valve, you will just send the cannister careening around the area, and very high and dangerous speeds. You would need a spark to set off the gas "after" it is escaping from the cylendar.

I did have a character once, take out a truck by knocking the valves off a cannister of compressed gas, causing the cannister to blow through the side. I gave it a 20D rating.

Myth 1, if you shoot a barrel of gas, or jerry can, it blows up.
Myth 2, you can take cover behind a car door because it will stop a bullet.
Myth 3, lead bullets create sparks when they hit metal.

As for altering environments, any smart group will take advantage of whatever they can,u sing flares, shooting out lights, rolling cars, sewer covers as shields.

There was also that time when we were preparing a vehicle ambush so we went out and bought a few truckloads of Jersey barriers, sheet metal, and plywood to stack around in a maze in the parking lot, but that's more creating the environment from whole cloth than modifying it.

~J

No they don't, but if the canister is constructed of a ferrous metal or there is some sort of metal components or loose stones in the area there can be plenty of sparks. There are also often other sources of ignition such as if someone fires a weapon, someone smoking, incandesent lightbulbs breaking, eletrical motors or other electrical equipment that isn't seald to be explosion proof, running combustion engines, etc.

EDIT: Theoretically the pressure that a slug creates when squeezing a flammable liquid between itself and a hard surface could create enough heat to ignite. This is how diesel engines ingite their fuel, they have no spark plugs. How likely this is to occur and what kind of conditions you need for it i couldn't say. The diesel engine has the benefit of compressing the fuel while it is mixed with oxygen in an engineered environment. If there is no oxygen present during the pressure then no ignition.

When a highpressure underground natural gas pipe blows it usually ignites the gas. Even out in the middle of the woods. Why? A spark from all the metal and gravel flying around.

P.S. Not all slugs are lead.

See, this is what I was talking about... How long does it take to roll over a car, or pry up a manhole cover without tools? (And who are these characters that are strong enough to roll over a car or handle a 100+ lbs chunk of steel as a shield?)

Instead of wasting time on that sort of thing, just take an action to run for the nearest corner or doorway while shooting - you'll have better cover, and any lucky shots that hit and do damage are just gravy.

One thing to keep in mind though is the huge amount of weight that this can involve. Dry sand weighs close to 2000kg/m3, or about 120lb. per cubic foot. Line a light-duty civilian truck box with sand bags and the wheels are likely close to touching the fender walls, and performance and gas mileage will suck.

Still a cheap portable foxhole, just don't expect to go rally driving with it.

I do agree on this whole heartedly. The barrier ratings on the walls of those cylinders, especially the acetalyne and oxygen ones, are going to be fairly high. Also due to the roundness they'd have a fairly small target to hit to keep even rifle slugs from just deflecting to the side.

As a side note once apon a time some very foolish engineering students at a local universty near where i grew up decided to improvise their own bottle rocket using a compressed gas cylinder. My understanding is they used a standard 3000 psi cylinder, likely compressed air since there was no ensuing deaths or explosions.

They set it up pointing across a local river at a point where it was maybe 200m to 300m wide. They then somehow broke the valve assembly off. Suppositly with the back side of an axehead. Given they were engineering students that means they were either very drunk (quite possible) or they actually rigged up something mechanical to fall and break it off while they watched from a somewhat safer distance.

Not sure if they had affixed guiding fins to it or anything to keep it mostly going straight, but the cylinder was found embedded in the soil of the bank on the far side of the river. This was well over 15 year ago so i can't give you a news link or anything.

For cutting fin slots you'd have to have a frame structure on the outside holding the quarter pipes in place.

You could have pop-out fins that are folded down inside the tube and that swing into place as they exit. There are modern tube launched weapons that do that.

The problem with rifling is that in a firearm the rifling actually deforms the slug slighty to put the groves into in and get traction. That is a lot of drag, and unless the rear of the tube is sealed you are going to lose a lot of push. If it is sealed you are going to need something stronger than PVC for the barrel. Also these cylinders are not as soft as a typical slug, certainly nothing PVC will push into. So you'd have to figure out something else to give the tube traction on the cylinder to put it into rotation.

Funny RL story... a friend and player of mine recently shot a used oxygen canister (the kind old people tote around) with his M-4 thinking that it was either empty or had been shot before (we were at a busy shooting area where idiots [like ourselves] often dump random shit to shoot at).

Before carefully considering what kind of ill shit might ensue, my friend shot the thing dead on. It exploded into a huge orange fireball with a white hot aura (the oxyen escaping) and disappeared. Or so we thought. It had actaully be launched air borne about 200m and landed about 5 seconds later ~150m away from where it had started (back and to the right of his position). Upon further examination it seems the particular idiots who had dumped it HAD shot it repeatedly with pistols and shotguns, but gave up out of boredom before they had quite ruptured the thing's shell.

The moral of the story: gas canisters ARE dangerous in RL, you just need an AR to light them up.

And a spark may not be nessisary. If you look at the ideal gas law (PV=nRT) its possible that rapid and extreme changes in pressure and/or volume could release enough thermal energy to ignite a highly flamible gas (like 02) spontaneously.

Not cutting all the way down. Leaving a length of solid pipe behind the fins.

~J