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Paintball Bullet/Paintbullet

Post about things you have launched or thought about launching. Also post about various materials used for building cannons. No posts about explosive projectiles!
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Paintball Bullet/Paintbullet

Unread postAuthor: Jolly Roger » Thu Mar 10, 2011 4:45 am

Hey guys,

So it's been a while since I posted on here and it's given me a bit of time to think about some different ammo designs.

Recently I have been thinking about trying to develop a paintball bullet.

I want to see how to improve the accuracy, velocity and range of paintballs, not so much to be used in tournament though. To do this I need to turn the ordinary paintball into a paintbullet to improve it's aerodynamics. I'd also like to try incorporate rifling which is a bit tricky.

I expect they will have to be made of gelatin like ordinary paintballs. They could be formed like a noraml paintball as such http://www.youtube.com/watch?v=gneZc_hafDE only with a half bullet shaped cast instead of a ball. This is fairly simple in theory.

Next I need to develop a rifling system. This is the tricky bit as the bullet will be subjected to high forces when fired and I don't want it to burst inside the barrel, and a rifled barrel doesn't allow the bullet to disperse its surface tension evenly along it's walls, increasing its chances of bursting.

That's where I thought about placing the bullet into a two or three piece sabot round like the picture attached. The two points on the edges are to slot into the grooves in the rifled barrel. I want to build the barrel so that that near the action where the bullet is loaded, the barrel opens up slightly like a flange so those two points can slot into them by themselves.

The only problem I see is that the sabot round may not come off the bullet straight away which would affect its accuracy. I need to figure out a simple way of getting it to depart from the bullet as soon as they leave the barrel. That's my main concern really.

Of course this design is not destined for use in painbtall markers, or paintball competitions because 1 it's not legal and 2 it would need a clip with a different action rather than a hopper which is not practical. I have different plans for it which I will post up later on.

If any of you guys have an idea for the sabot or anything else really, please comment. It would be much appreciated.

Cheers,

JR
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Unread postAuthor: ilovefire » Thu Mar 10, 2011 5:37 am

didnt read your whole post but do you mean something like this?
http://www.google.com.au/imgres?imgurl= ... 29,r:1,s:0
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why make it if it dosent shoot?
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Unread postAuthor: jackssmirkingrevenge » Thu Mar 10, 2011 5:39 am

The only problem I see is that the sabot round may not come off the bullet straight away which would affect its accuracy.


I would be more concerned about the fact that you're attempting to gyroscopically stabilise a projectile with a liquid core.
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Unread postAuthor: ilovefire » Thu Mar 10, 2011 5:45 am

better link, sorry for the size but i forgot how to do the JSR thing
http://www.google.com.au/imgres?imgurl= ... 76&bih=684
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why make it if it dosent shoot?
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Unread postAuthor: jackssmirkingrevenge » Thu Mar 10, 2011 6:29 am

ilovefire wrote:better link, sorry for the size but i forgot how to do the JSR thing


Image

Of course this design is not destined for use in painbtall markers, or paintball competitions because 1 it's not legal and 2 it would need a clip with a different action rather than a hopper which is not practical. I have different plans for it which I will post up later on.


You want a paint"ball" round that won't be used for paintball :?
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Unread postAuthor: Jolly Roger » Thu Mar 10, 2011 6:33 am

ilovefire wrote:didnt read your whole post but do you mean something like this?
http://www.google.com.au/imgres?imgurl= ... 29,r:1,s:0


Yeah something like that. Theirs is really interesting. Cheers for that.



jackssmirkingrevenge wrote:
The only problem I see is that the sabot round may not come off the bullet straight away which would affect its accuracy.


I would be more concerned about the fact that you're attempting to gyroscopically stabilise a projectile with a liquid core.


Very True. I haven't done much physics since high school to be honest so I'm a bit unsure here. What would likely happen if I tried to make it spin? If I put a divider down the middle of the bullet to create 2 sections forcing the liquid to spin, would that make any difference?


jackssmirkingrevenge wrote:
ilovefire wrote:better link, sorry for the size but i forgot how to do the JSR thing


Image

Of course this design is not destined for use in painbtall markers, or paintball competitions because 1 it's not legal and 2 it would need a clip with a different action rather than a hopper which is not practical. I have different plans for it which I will post up later on.


You want a paint"ball" round that won't be used for paintball :?


Traditional paintball anyway.

Edited by jrrdw, triple post.
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Last edited by Jolly Roger on Thu Mar 10, 2011 6:42 am, edited 1 time in total.
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Unread postAuthor: Crna Legija » Thu Mar 10, 2011 6:52 am

you can try your self with a egg spin a boiled eggs and compare its time with a raw egg

edit: use the edit button no need to triple post
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Unread postAuthor: Jolly Roger » Sat Mar 12, 2011 12:51 am

-_- wrote:you can try your self with a egg spin a boiled eggs and compare its time with a raw egg

edit: use the edit button no need to triple post


Cheers for the heads up, been a while since I posted.

With the liquid however, if I put a divider down the middle of the round wouldn't that solve the issue of the bullets liquid centre not gaining inertia when fired?
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Unread postAuthor: jackssmirkingrevenge » Sat Mar 12, 2011 1:41 am

With the liquid however, if I put a divider down the middle of the round wouldn't that solve the issue of the bullets liquid centre not gaining inertia when fired?


Technically yes, but it also complicates manufacture.

I want to see how to improve the accuracy, velocity and range of paintballs, not so much to be used in tournament though. To do this I need to turn the ordinary paintball into a paintbullet to improve it's aerodynamics. I'd also like to try incorporate rifling which is a bit tricky.


Basically you're trying to create a paintball sniper rifle, right?

I think you need to look at the wider picture first.

For long range, you need three major factors:

velocity: the faster a projectile is going, the flatter its trajectory will be, and the less time it will have to be affected by environmental factors.

projectile density: the denser a projectile is, the better it will cut through the air and it will lose velocity at a lower rate.

aerodynamic shape: reducing drag also has the same as projectile density, allowing it to go faster for longer.

Unfortunately for the purposes of non-lethal paintball, the above also makes projectiles optimised for penetration.

What exactly is the range you're aiming for?
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Unread postAuthor: Jolly Roger » Sat Mar 12, 2011 3:13 am

Well I'm looking at eventually designing a rifle that is effective at long range upwards of 600 yards. What you said is spot on which is why I have been toying with range finders recently and have managed to get a mate who is currently studying electronic engineering to hook one up to a servo for me. He said it was relatively easy, but I have no idea how I would go about it. He set it up at 500 metres where the servo is fully engaged, and only 5 degrees when the range finder signals 10 metres (servos range is 180 degrees).

What this will do in practice is change the amount of pressure behind the projectile relative to how far away the target is, making it in theory safer. This will need a lot of field testing and adjusting though to make sure the energy in the round, when it breaks on target, is safe and consistent when fired at both close and long range.
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Unread postAuthor: jackssmirkingrevenge » Sat Mar 12, 2011 3:53 am

Jolly Roger wrote:Well I'm looking at eventually designing a rifle that is effective at long range upwards of 600 yards.


I would say that is far too ambitious.

Let's take theVSS suppressed sniper rifle that fires a 16 gram bullet at the subsonic velocity of 920 feet per second. Its trajectory limits it to a range of 450 yards effective range, and it can defeat body armour at that range.

It would be conceivable to build a hybrid spudgun that can be accurate at 600 yards, but the projectile would not be paint filled and it would not be safe to fire at anything animate.

To hit a man sized target at 600 with a direct fire launcher, the projectile would have to be at least supersonic, and a projectile secure enough to survive being launched at that velocity will definitely penetrate flesh.

It's difficult enough to hit a 45 gallon drum at 100 yards using a 0.22" air rifle firing a small dense lead projectile at twice the velocity of a typical painball marker, even if there is absolutely no wind.
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Unread postAuthor: Jolly Roger » Sat Mar 12, 2011 9:22 am

Yeah that's fair enough too.

Although I'm just doing a few calculations on some sites that allow me to factor in a few more things such as drag, bullet shape and density, twist, muzzle velocity etc. and I'm getting a drop of 13 metres at 600 yards off a 900fps shot (9mm boattail design). It's reading 60 joules at 50 yards which is fairly high though. Still I'll play around with it some more to see if I can get that number down because a drop of only 13 metres at 600 yards is pretty good. I know the military here consider less than 35 joules a non lethal round so I'll aim for around that.

Even if I do get something out of it though, I still have to consider the possibility that the round may simply not be up to it at those velocities like you said. One step at a time though I guess.

Hey also, I stumbled across this story about a guy who has won a small business award from the Pentagon by basically building a hydrogen powered spud gun. Thought it may be of interest.

http://www.popularmechanics.com/technology/military/weapons/toymaker-turned-weaponmaker

I've toyed with this idea for ages, having the ability to adjust the power of a weapon like that with combustion/hybrid cannons for use in the field. Was just a bit surreal to come across it like that, exactly how I had seen it.

Anyway, I'll keep playing around with these numbers and post the results shortly.

Cheers
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Unread postAuthor: jackssmirkingrevenge » Sat Mar 12, 2011 10:19 am

Jolly Roger wrote:I'm getting a drop of 13 metres at 600 yards off a 900fps shot (9mm boattail design). It's reading 60 joules at 50 yards which is fairly high though. Still I'll play around with it some more to see if I can get that number down because a drop of only 13 metres at 600 yards is pretty good.


You'd definitely need a rangefinder to get the exact distance, and some way of accurately estimating the effect of wind - if it significantly affects a dense bullet travelling at several times the speed of sound, you can imagine what effect it will have on a large relatively slow paintball projectile.

Jolly Roger wrote:I know the military here consider less than 35 joules a non lethal round so I'll aim for around that.


On the other hand, there are several documented cases of people being killed by single shots from 16 joule air rifles, so you certainly have to be careful.

Jolly Roger wrote:Hey also, I stumbled across this story about a guy who has won a small business award from the Pentagon by basically building a hydrogen powered spud gun. Thought it may be of interest.

http://www.popularmechanics.com/technology/military/weapons/toymaker-turned-weaponmaker


Interesting project, we had touched on it here.
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Unread postAuthor: ramses » Sat Mar 12, 2011 11:57 am

I had at one time been planning something similar to your rifle. I planned mounting the scope on a hinged mount, and angling it with a lead screw and stepper motor. I was going to control veloicty by changing the mix of the hybrid (yes, it was going to be hybrid). I was going to use either pitot tubes or hot wire anemometers to measure wind at the rifle.

How do you plan on interfacing with the rangefinder?
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Unread postAuthor: Jolly Roger » Sat Mar 12, 2011 9:19 pm

ramses wrote:I had at one time been planning something similar to your rifle. I planned mounting the scope on a hinged mount, and angling it with a lead screw and stepper motor. I was going to control veloicty by changing the mix of the hybrid (yes, it was going to be hybrid). I was going to use either pitot tubes or hot wire anemometers to measure wind at the rifle.

How do you plan on interfacing with the rangefinder?


How come you stopped designing it?

I bought a 'Legend' range finder off Ebay last year thinking I could somehow tinker with it and hook it up to a servo. As soon as I got it I looked at it and went, I have no idea what I'm doing. So I hit up a mate of mine who has taken the bottom of it apart and put it onto an electronics board. He's also got a USB connection on it where I can plug it into his laptop and can change the output to the servo depending on the inputs he gets. At the moment though it takes a good second or so for it to measure a distance, then align the servo.

With this I want to get the servo to control a ball valve in the chamber or barrel that diverts pressure away from the barrel when the range finder signals a close target and opens it up completely when the target is at a distance. That way I can keep the same hybrid mix in the chamber and not have to adjust that each shot as that would be quite timely.

As far as crosswind goes though, that will be an issue. There's nothing really I can do apart from manually adjusting my shot based on what I see, unless I can somehow hook up a scintillation anemometer to a ballistic computer which would be awesome but I might have raid my piggy bank for a spare 10 thousand or so first.

Like Jack said though, I think 600 yards is too ambitious now. I should change my goal from being effective at 600 yards, to being able to shoot to a distance of 600 yards, effective at maybe 200. I think that's a bit more reasonable.
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