Crossbows

Discussion in 'General Science & Technology' started by Avatar, Jan 17, 2008.

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  1. Myles Registered Senior Member

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    My uderstanding is that angling it upwards like a rifle would cause the bolt to describe an arc. I may be wrong.

    Why not google " crossbow trajectory", look at the BBC site and tell me what you think ?
     
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  3. Myles Registered Senior Member

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    Haf u no black market where you lif ? Vare is dat ?
     
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  5. phlogistician Banned Banned

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    For sure he did, I used to shoot rifles and do archery, and whether the projectile travels up first, or begins falling, depends solely on the inclination of the weapon, and nothing else.

    With rifles, if you are standing up, and you want to hit a man sized target in the head at some distance, the rifle must be angled up so the bullet can rise and fall. You perhaps don't even realise you are doing this, but that's what the elevation correction on the sights do; they alter the tilt at which do discharge the weapon.

    With a crossbow, the sights are the same, so you'd angle upwards. (unless shooting downhill, of course!)

    Now, with a bow, I used to shoot 'bare bow' ie, no sights, counterweights or aids of any sort, you have to come up with some way of judging the angle for a shot, and there are various methods, depending on your archery style, and where you pull the arrow. I prefered to pull the knock to under my eye, and sight along the arrow, allowing for offset (being right handed, the arrow would be on the left side of the bow) and drop, using my knuckles as elevation markers, and comparing relative distances against my hand size too.(works up to about 60m, after that, you need a bigger drop). At my best I could hit a 4" target at 25metres (we used to use Digestive biscuits, they were cheap, and shattered when you hit them) from varying elevations.

    Of course, if you are shooting at any other angle other than flat level, the amount of drop you allow for is less, whether you are shooting upwards, or downwards. You would always calibrate your sights for level shooting therefore, knowing that at whatever range you have them dialled in for, the drop will be less if the shot is angled.

    Of course, rifle sights can be set for two ranges, as the sights look in a straight line, and the bullet an arc, unless you have the sights dialled in to lie across the tangent of the arc (this depends on range) they line of sight will intersect the arc twice, one at closer range, and once again as the bullet drops significantly more. Perhaps not much use to full bore shooters, but lots of use to folks that shoot air rifles, being low power, these two intersects are at workable ranges, and using a parallax adjustable scope, you can use the focus bell to determine the range, and know which intersect you are closest to, and work out how much over or under you are. A quicker method is to use a laser mounted above the scope, to spot your target at your dialled in range. If you are closer, the spot will be above the target, further away, lower, and you can gauge drop using this method. (this is more use to full bore shooters)

    Anyway, that's enough ballistic geekdom for now.
     
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  7. Myles Registered Senior Member

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    Agreed. It's all about the projectile falling under the force of gravity. As the distance fallen is proportional to the square of the time. it can be shown that the trajectory is an arc, even if one assumes that the projectile travels at a constant speed.

    I have never used a gun.
     
  8. phlogistician Banned Banned

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    Well, to be honest, there's nearly as much fun to had with an airsoft, or air gun, as a full bore gun, except the first two are much, much cheaper to shoot, and far safer!

    In fact, shooting old fashioned spring powered airguns is pretty good practice for moving up to real guns, a spring powered airgun will have more recoil than a 0.22 rim fire, so if you have good technique with an air rifle, moving onto rim fire target rifles will be a breeze.

    If you do get interested in shooting, first check out the legalities, and make sure you observe them, 2nd, get instruction- learn by other's mistakes, not your own, 3rd observe safety, and 4th, more safety. It's only fun while everyone is safe.
     
  9. GeoffP Caput gerat lupinum Valued Senior Member

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    All fery interesting, yes, but vhat vill he use against Gypsies, hah? Maybe he gets mirror to shoot backwards in so not have to look them in the eyes.
     
  10. Orleander OH JOY!!!! Valued Senior Member

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    Have you seen the paper crossbow they made on MythBusters?

    Adam and Jamie unleash a deadly myth from a supermax prison, attempting to make a deadly weapon out of newspaper and underwear.
     
  11. Myles Registered Senior Member

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    Paper and UNDERWEAR. Why do you bring sex into everything. Go and have a cold shower, you sinner.

    That picture of the Canadian turkey you sent me is disgusting. The more I looked at it , the more disgusting it became. After 2 hours I couldn't take any more. I shall have another look today to make sure I am right. I'm a greater believer in being fair.
     
  12. Orleander OH JOY!!!! Valued Senior Member

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    oh Myles you crack me up. LOL.
    Uh-oh, and where is a crack....my perversions have gotten out of control!!!

    So, is the Canadian pic still disgusting?
     
  13. I-Am-Invisible sick of it all. Registered Senior Member

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    this is what i think, if you want a effective way of defending yourself in "the wild" i'd go for a rifle, a bolt-action rifle will do fine. the problem i see is that animals have a much greater sense of awareness and percieve things much better then we do so if it comes to closequater combat you'll definatly have difficulties even with advanced martial arts skills. there for you the animal must be dealt with before it reaches you. now comparing a crossbow and a firearm is easy: the firearm has a bigger range, higher rate of fire and is less affected by wind...

    as i said before i would get a bolt-action rifle, it's easier to get a permit compared to a handgun or a semi-auto rifle and its easier to shoot. many people people shoot rilfes as a sport and requires koordination of breathing, aiming and triggercontrol. best you contact your nearest shooting range and ask if you can come by and try it out. i advise the same thing with the crossbow, you will quickly realise what will suit you...
     
  14. Avatar smoking revolver Valued Senior Member

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    Not in Latvia, actually it's harder to get a rifle - you have to be a registered hunter besides passing all the other tests and checks. You can get a hunter permit only after you have passed hunter tests (including practical participation in hunting), and I've no intention in doing that, because I don't eat meat and find hunting bad.

    I have lots of experience with firearms, including machine guns, hunting rifles and pistols. A rifle would be good, but too big, heavy and noticable.


    I've settled for a spear in addition to my pepper-spray, and maybe a ruger revolver, or a s&w model 10.
     
  15. Myles Registered Senior Member

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    As I said, I am fair; I do not make snap judgements. I shall need to spend several more hours a day over the next month before deciding.

    Can I interest you in my recent self-help book ? It's called:

    How to live without sex for one hour a week
     
  16. river-wind Valued Senior Member

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    This is what I was going to recommend. My favorite anecdote about the atalatal is that when the Spanish conquistadors arrived in the Americas, they were horrified to discover that the atal bolts could easily pass through the metal armer they wore. Plus, the atalatal launching arm can double as a club for hand to hand combat.

    Very powerful, yet simple, devices.

    Plus, if you have a single long shaft and a dozen tips (the point plus another 6" of shaft), you can re-use the longer shafts for multiple throws - the impact bounces the shaft off of the tip; you can then walk over and pick it up off the ground at your leisure. Much easier than carrying a dozen full spears.
     
  17. GeoffP Caput gerat lupinum Valued Senior Member

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    A decent suit of mail and ring barding for your warhorse would probably go a long way towards reducing injury also.
     
  18. Avatar smoking revolver Valued Senior Member

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    It's very heavy. A friend of mine makes ring mail armor for medieval fighting clubs - not the stuff to hike in.
     
  19. phlogistician Banned Banned

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    I have a chainmail vest, used to do re-enactment and LARP. My vest is made out of quite thick wire, but is only short, and weighs 20lbs. Moving in it is OK, stopping or turning quickly a very different matter. Hiking would be awful.

    I once got quite drunk at a banquet, and slept in it. My shoulders ached like hell the next day!
     
  20. fusion4577 insane, atheist, and not dead Registered Senior Member

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    i guess a crossbow would be the most effective, heavy, but effective. also, i think self defence is worth a bit of troble with the law

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  21. Avatar smoking revolver Valued Senior Member

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    No, it isn't. Especially if you are working for the law.
     
  22. elte Valued Senior Member

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    I have a crossbow which has pulleys on the ends of the prod. It allows a shorter bow to have similar propulsion characteristics as a longer one. It also has a pivoting stock lever which makes cocking easier and a little faster.
     
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