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Solid balls in the UK....

Munkeh

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You actually have another variable to consider which is amount of time in contact with the body, but I won't bore you with the maths involved.

Just to question your physics Red, ok F=ma :- Newtons Second Law... but what is the acceleration on the ball when it contacts a person? OR during contact? Just wondering here of course...
 

Red_Merkin

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Jul 9, 2001
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the acceleration, (or deceleration as the fact may be) also depends on the distance.
300 fps is guanteed at a foot, because that's where the chrono reads the ball roughly, but hardly anyone ever gets shot from that distance, unless they get mugged.

At that distance most paintballs would break, even ones that had been cured thru improper storage.
 

Munkeh

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I think you find acceleration of the body in free flight makes no difference to the force applied to a body upon impact. This is governed by momentum not by acceleration!

For all you maths geeks out there :-
The equations that should be used for impacts are as follows (These imply no deformation or rotation involved. So much simplified!)

Ft = mu-mv [Impulse = change of momentum]
and -eU=V [e=coefficient of restitution i.e. how bouncy something is!]
 

Red_Merkin

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the speed at which a ball happens to be traveling...
the force applied to the body, is equal to the speed the ball is traveling at the point of impact, multiplied by the weight of the ball. If speed and mass are the same, then the force should be the same.

The practical difference is whether the ball crumples on impact or remains solid.

I maintain that the force of a solid ball, (rubber or foam) that weights the same as a .68 calibre paintball, and has the same volume, will hurt the same as a 'bouncer'; a ball that does not crumple or break on contact.

Do you agree or disagree?
 

Munkeh

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Well I did just edit my post. You are partly right, but for the actuall force applied you need to look at rate of change of momentum.
 

Munkeh

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Well I was assuming that the person would be assumed to be solid. Untrue I know... but makes the calculations easier!

[Edit] Having just thought about. The only difference a fat person would make is increase the time in contact so decrease the force. {See Earlier Eqtn} So it should be tested on a really skinny person. :D
 
O

ollytheosteo

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Too much physics- my brain hurts!

Guys- thanks for all the input (except the beating off stuff- c'mon, this ain't that kind of party) and useful comments. I'm worried the thread is getting distracted; I don't feel that these balls are particularly dangerous per se, but I do worry about the legal situation in the Uk. Paintball guns are exempt from most firearms laws because the projectile they fire is frangible and "non-lethal". The second you put a non-frangible hard pellet in a paintball marker it can be argued that it should be defined as a lethal barrelled weapon as it will have a muzzle energy in excess of 1.35 J (about 8-9 times that energy in fact). Airsofters are facing legal difficulities with regards to firing 0.2g bbs at over 377fps, so a ~3g plastic ball at 300fps is definitely classed as "lethal" under the law. It's one thing to say that someone might try and put a ball bearing etc into a paintball marker, as they are not designed for such a projetile. Marketing a ball designed for firing through a marker could lead to convoluted UK laws lumping paintball markers in with other airguns, making the legal situation very shaky indeed. I think in principle the idea of a re-usable hard ball for target practice is a great idea, but under UK law it may lead to a very nasty mess, as we define lethality in terms of muzzle energy, and whilst markers firing paintballs at some velocities is ok, firing anything else can take the marker over legal lethal levels. The "safe" velocity under UK law for firing reballs etc could be interpreted at around 30fps. We need to urgently discuss this issue with the HO before these balls become widely available in the UK. :eek:
 

JoseDominguez

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Oct 25, 2002
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Originally posted by Red_Merkin
did you actually read what I wrote (apart from the last line which somebody is kindly editing for me, thank you kindly, but please stop)

I said, when assessing safety, you have to assume that the paintball won't break, because that's the most damage that it will cause...
Yes there are other variables, how much deformation a solid ball will cause, but a solid ball will deform too. Take a look at high speed video footage of a baseball deforming when hit by a bat. Although a baseball appears to be solid, it will deform quite a bit. So a solid paintball will have some amount of deformation too.
The unknown variable is how much difference there is between a paintball that doesn't break, and a solid ball. If the size and weight are the same, and the ball doesn't break on impact then the amount of force on impact will be in theory, the same.

Paintballs that won't break do exist, we got a load of Zap two years ago after campaign cup, and this stuff would ricochet off trees. Dangerous yes, lethal, no. I got shot with it, and I'm still standing... so I know that even a solid paintball that won't break on target is still not capable of seriously hurting someone.

As for the tests in Scotland, they were done by loading a shot with a different density (therefore a different mass) to prove solid shots from paintball guns could be lethal.
There's a big difference between a .68 calibre shot of a rubber paintball, and a .68 calibre of a solid steel ball!

So
the variables are:
the weight of the ball... the solid ball is advertised as being the same weight as a standard paintball
the speed of the ball... both are being shot at 300 fps, and should be travelling at the same velocity
the amount of force absorbed by the ball... if a paintball is too hard and doesn't break, it should absorb a comparable amount of energy to a solid ball, and transfer a similar amount of weight to the target. If there is a massive difference in this factor, then the whole thing doesn't work, but for two objects to be the same weight and volume they must have similar structural characteristics.



Does a solid training ball pose more of a risk than a premium paintball? Of course
Does a solid training ball pose more of a risk than a badly stored and very hardened paintball? Probably not.
Do current safety standards account for players using improperly stored paint? I don't know, it hurts like hell, but I've still got all my body parts, so probably no.
Do players ever use improperly stored, hardened paint? You bet your ass they do, cause I've been shot with some seriously hard paint, and it hurts like hell!

I'm aware that you teach Physics...but that doesn't meant that you don't actually have to read what I've written. In fact as a teacher I'd expect that you pay more attention to the argument being presented. If I'm wrong, then I'll admit to it, but you have yet to actually address what I've written!

And whoever is editing my posts, please stop. You have the job of editing out inappropriate material, not changing my post for your own pleasure. Thank you.
I read everything that you've written, and my point is that even if a paintball doesn't break it deforms as even the worst stored paint on the planet is not solid................... there's still paint in there but the shell has toughened up. Only one way to find the effects of a totaly solid paintball...... that's to freeze one solid.... now that will cause a dam site more damage than a badly stored one. The make up of the projectile is very important...... a paintball (even a bouncer will still spread it's weight over your skin as it hits.... go from 1 cm square of contact to 2cm... you've just reduced the pain by half)
And my worry is still the same......... a hot marker firing a paintball at well over 300 will hurt, it will hurt a lot........ but the ball is going to pop (OK maybe one or two won't) but solid balls?
I don't know what effect they'll have.......does anyone? just because they weight the same and are of equal volume, doesn't mean they'll have the same impact.
Anyway, the big issue is how the UK legal system will view these things.

just lifted this from the CPS site
Paintball guns are a form of air weapon. It is arguable that they are prohibited weapons under section 5 of the 1968 Act. However, the Home Office regard self-loading or pump action rifled airguns (including paintball guns) as outside the scope of section 5, unless they are sufficiently powerful to fall within the category of a "specially dangerous" air weapon (Archbold, 24.8a

So it's arguable that markers are already prohibited? what about if we start altering our nice bursting ammo?