big airguns

Do not be deceived. This website is purely to induce you to thrust a hand inside a hip pocket, extract a wallet, pluck large denomination banknote therefrom, walk cheerily into your bookshop, and purchase a copy of http://www.merlinunwin.co.uk/bookDetails.asp?bookId=9&categoryId=1which, I now confess, will increase my royalties by a vast but indeterminate sum.The photo to the right is my first muzzle-loading big-bore airgun, a monstrous thing which my friends immediately called The Jezail. The barrel was a two-metre length of copper pipe extracted from the local plumber's merchant, and the air reservoir a piece of bicycle inner tube - cunningly incorporating the valve so it could be inflated hard - poked into a tube of sewn sailing webbing. The webbing prevents the inner tube expanding like a large and bulbous party balloon, so the air pressure goes up which is what we evil people want it to do. Air can't get out of the back of the tube because it is clamped between two bits of angle iron, and it can't go out of the front because there's another clamp in the way. This second clamp, however, can be flicked open by the sideways-poking toggle thingy, and then all the air is released instantaneously behind the bullet. If you happen to be a concert pianist then get someone else to do the flicking, because once it's past the centre of the various pivots that hold it shut, then the air snaps the lever open very hard, and it is quite indifferent to whether or not you want your fingers amputated.If you can't work out exactly how the trigger functions, the exact mechanism is neatly drawn on page 135 of the above-mentioned book - did I mention that I want you to buy a copy? - and, because I'm Hugely Clever, if you turn the page you can find an altogether safer mechanism on page 138. Actually, on page 136 there's a mechanism that can be built entirely out of wood. I'm perverse like that. I like to use inappropriate materials in gun-making. I can't see any reason why, when the Penan tribesmen of Borneo managed to make six-foot blowpipes in the jungle with nothing more than a steel stick as a drill, we should find it impossible to make an entire gun out of wood.I used a pressure of no more than 11 bar (160 psi) because that's what my bicycle pump was capable of. At this pressure and with two metres of plastic conduit for the barrel, and a larger air reservoir so that the thrust down the bore remained high, I shot a 16mm glass marble weighing 84 grains at 721 feet per second, and since this is the sort of thing that politicians around the globe are extremely keen that you do not do, it's probably as well to check your local laws before you embark on a wicked enterprise like this. (Where I live, outrageously powerful airguns are legal. Amazing but true. It's why I live here.)Should you have no chronograph, you can estimate velocity of a lead ball by shooting it at a brick. This can be quite exciting, especially for bystanders, because recovering the ball afterwards may involve searching the immediate environs which could include indentations in the bodies of the audience. The picture below shows what happens to a half-ounce lead ball shot at 192 feet per second at a brick wall, all the way up to 332 feet per second at a brick wall, which valuable information was obtained not without hazard to self and neighbourhood. A half-ounce ball is .527 inches in diamter, and wrapped in a whisp of tissue paper, fits neatly inside 15mm copper pipe sold for the more mundane purpose of plumbing.