I tested using steel drill bits as projectiles out of my smoothbore .177 coaxial gun, and the grooves in the bit acted as rifling and enabled the bit to fly straight and penetrate deeply without fins. I don't have the means to test this out from far away, or at stronger targets such as steel sheets so if anyone wants to try it.(JSR? )
[youtube][/youtube]
Using drill bits as "rifled" projectiles
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What was the approximate range...muzzle to target, and how reproducible were the results?sagthegreat wrote: I don't have the means to test this out from far away...
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at 10 feet away, 9/10 of them self stabilized
at 20 feet away, 7/10 of them self stabilized
at 30 feet away, 5/10 of them self stabilized
What i wanted to test was like 50-100 feet away
at 20 feet away, 7/10 of them self stabilized
at 30 feet away, 5/10 of them self stabilized
What i wanted to test was like 50-100 feet away
It doesn't sound like it's self-stabilising then, at least not efficiently enough to be worth the high cost of drill bits.
I wouldn't be surprised to have similar proportions of unstabilised projectiles not yet tumbling at those distances.
I wouldn't be surprised to have similar proportions of unstabilised projectiles not yet tumbling at those distances.
Does that thing kinda look like a big cat to you?
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If they appear stable, I would wager it is more to do with the nose heaviness than the projectiles spinning, air rifling doesn't really work.
It's cheaper and more effective to thread a bolt into a length of tube.
If it worked, 10/10 should hit head first at 30 feet.at 10 feet away, 9/10 of them self stabilized
at 20 feet away, 7/10 of them self stabilized
at 30 feet away, 5/10 of them self stabilized
It's cheaper and more effective to thread a bolt into a length of tube.
hectmarr wrote:You have to make many weapons, because this field is long and short life
Well, it's worth saying that you'll sometimes find projectiles with angled fins in order to induce spin (the first example to mind is the RPG-7), but it's not for stability.jackssmirkingrevenge wrote:air rifling doesn't really work
It makes any imbalance in the drag of the projectile average out in all directions, causing it to take a slightly helical trajectory rather than a hooking one.
Does that thing kinda look like a big cat to you?
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The thing is, I load then with the "drill" end first, which is lighter due to material being taken out to form the drill pattern, and they all hit with that side going into the targetjackssmirkingrevenge wrote:If they appear stable, I would wager it is more to do with the nose heaviness
I tried from 25 feet vs a steel lid and they perform great! Compared to just shooting a steel rod, a drill bit has a way better chance of self stabalizing
[youtube][/youtube]
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[youtube][/youtube]
I have to try this...
edit: I was unable to replicate your results at 15 feet, here's 5 shots fired head first at a cardboard box:
I tried different bits and got the same results, even when firing them tail first - none of them flew straight.
I would surmise that you're not seeing the tumbling because of the high velocity and short distance.
Have a look at this unstabilised unrotated projectile fired at supersonic speed:
[youtube][/youtube]
It starts to tumble immediately, but for the first instants of its trajectory it is still travelling more or less straight enough to make a round hole in a target.
I have to try this...
edit: I was unable to replicate your results at 15 feet, here's 5 shots fired head first at a cardboard box:
I tried different bits and got the same results, even when firing them tail first - none of them flew straight.
I would surmise that you're not seeing the tumbling because of the high velocity and short distance.
Have a look at this unstabilised unrotated projectile fired at supersonic speed:
[youtube][/youtube]
It starts to tumble immediately, but for the first instants of its trajectory it is still travelling more or less straight enough to make a round hole in a target.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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that video pretty much summarizes it then...
just out of curiosity, what type of cannon did you use, and what material did you use for wadding?
I used my coaxial with 12 inch barrel and 200psi, with a pellet as a backing
just out of curiosity, what type of cannon did you use, and what material did you use for wadding?
I used my coaxial with 12 inch barrel and 200psi, with a pellet as a backing