Tim May wrote:
On Thursday, November 29, 2001, at 04:32 PM, keyser-soze@hushmail.com wrote:
Have any of the shootingpunks on the list heard of constructing a firearm from something akin to a internal combustion chamber?
H&K was a prime contractor on the "caseless ammunition" system being considered for a bullpup rifle to replace the .223 variants. Fired three flechette-like projectiles, no case. (Cases add weight, and in principle one could dispense with them.)
Cases also have to be ejected. In principle, you can have a simpler mechanism and a higher fire rate if you use caseless ammo. (In practice, the only automatic caseless rifle I've seen (not an H&K) had a mechanism virtually identical to any other gas operated automatice, down to the ejector hook in case of a bad round.)
If you mean something that runs on fairly conventional fuel, such as diesel or gasoline or alcohol, t's unlikely that enough muzzle velocity will be achievable in a reasonable-length barrel.
Right, petrol won't burn fast enough for direct propulsion. You might be able to use a large combustion chamber and then neck down to get a higher gas velocity, but (in the absense of actual calculations) I don't think that would get you enough. I suppose you could use something like space shuttle fuel; that burns pretty fast. Of course, it's volatile, instable, corrosive, and expensive...
I did see a GyroJet pistol once. A rocket pistol, firing little rockets. Early 60s. Very expensive. And suffered from the fact that each little rocket had to accelerate up to speed. Lots of chance for the target to move.
Gyrojet rounds burned out in, IIRC, 20 feet, and they covered that first 20 feet in a small fraction of a second. I don't think target dodging is any more of an issue than with conventional bullets. But the burning fuel might be a problem in another way: what if you shoot someone who's less than 20 feet away? The rocket would keep burning after it struck. Would that be viewed as torture, if you were investigated for the shooting, be the shooting ever so justified? (Data points: I've never pointed a pistol at anyone farther than about six feet away. Once was under a foot. (Passenger in a small car tried to rob me with a knife.) This is the norm for people who are actually shot with pistols, as contrasted with being shot at.) -- Steve Furlong, Computer Condottiere Have GNU, will travel