Why .68? Why not .40 or .50 or .60?

[Jack & Coke]

Why .68? Why not .40 or .50 or .60?

Has anyone ever tested the flight characteristics of a .40, .50, and .60 size paintball with similar impact energies as a .68 @ 300 fps?

Right now we have "standards" of .68-.69 @ 285-300 fps accepted as "safe" impact conditions.

How about a slightly smaller size and lighter weight paintball @ slightly higher velocity?

or

Smaller size, increased density paint?

[irbodden]

By shooting a smaller paintball FASTER wouldn't it be more likely to hurt?

It is too late now anyways, .68 is industry standard, it would be near impossible to change it.

[FrAuStY]

I do know they make .40 caliber paintballs...but evidently they weren't as accurate as the current size/fill even then..yes... smaller shells would hurt more at higher velocities. Its similar to the armor piercing shells... smaller bore..higher muzzle velocity pierces better than larger bores at lower velocities.

[manike]

I've made this post before

Ok I'll tell you why :) The velocity limits we have are actually set not because of velocity but because of projectile energy. Now the powers be have deamed that 12ft/lbs is the maximum 'non lethal' energy. This energy is a factor of mass and velocity squared. That is why lighter projectiles can fly at higher velocities used to be allowed as they still have the same energy.

Ok so far?

Now how much energy a projectile has determins how quickly it is slowed by external factors.

The energy is actually related to mass and the velocity squared.

The resistance forces to pojectile motion are related to the frontal area of a projectile and increase by velocity squared.

Objects with a higher mass have a greater momentum and are less subject to being overcome by resistance forces. It works out with a sphere that a larger diameter and the resulting weight increase actually gives it more energy than the increase in size creates drag.

This means that with the same material a spherical object will conserve more energy in relation to wind resistance the larger it is. A smaller object at the same velocity will have less energy and so be more quickly overcome by resistances to motion (drag) and be more likely to be blown off target by wind and air currents.

Thus the more energy it conserves against resisitive forces the further it will fly. The larger and heavier you make your projectile the further it will fly given that it started with the same velocity as a smaller sphere.

This is partly due to air resistance increasing at the square of velocity and energy also increasing at the square of velocity times the mass. The first one working more against small projectiles flying quickly and the second factor working for heavier objects flying at the same speed or slower.

There endeth the lesson

One other reason that that smaller projectiles are not used is that they put the same energy into a smaller part of the target. This means more pressure. Smaller projectile have been experimented with and in some cases were found to penetrate clothes... and people!

The volume of a .68 cal ball will be 0.165" cubed. The volume of a .40 cal ball would be 0.034" cubed. Making the volume of the .40cal ball just 21% (or one fifth approx) of the .68 cal ball. Since the density of the material we are making it from is pretty much the same, that also means the .40 cal ball would have about 1/5 of the weight of the .68 cal ball.

At the same velocity the .40 cal ball would have about a fifth of the energy of the .68 cal ball. There fore it would go a significantly less distance and be less accurate as it would be more susceptible to outside forces

It would also have only one fifth the fill volume to be able to leave a splat mark with... We all know how hard it is sometimes to determine hits at the moment... we need all the 'splat' we can get

The best paintballs for energy and thus range and (thus breaking at distance) are the largest, heaviest paintballs you can find. If you could make a smaller heavier paintball then this would be better, but in general terms since the material is the same density, making it larger will give more benefit from the energy due to extra mass than it will forfeit from the increased wind resistance.

Heavier balls will fly farther. They have more energy at 300fps. In fact if you make them too heavy they go outside of what is legal in terms of the projectile energy limit. The best heavy paint I ever shot was called Forest Heavy (from WDP) and flew like a dream... It was also rumoured to be right on the limit (if not over ) what was legal...

Heavier balls will have more energy in them when they reach your target, especially at longer ranges, this means they are more likely to break and mark rather than bounce...

Heavier balls will hurt more (they have more energy) and will hurt even more if they bounce (greater change in momentum and no energy dissipated in the breaking of the ball... p.s. that why bouncers always hurt more

Heavier balls at 300fps have taken more energy to get to that velocity, this means you will get less shots per tank fill as you are using more energy from your tank per shot.

I'm a back player. I like heavier paint

manike

(If I got any maths wrong it's cos it's late and I'm tired and I didn't check or edit my earlier posts :) )

[Jack & Coke]

Originally posted by irbodden
By shooting a smaller paintball FASTER wouldn't it be more likely to hurt?

Not if it has less mass.

Originally posted by irbodden
It is too late now anyways, .68 is industry standard, it would be near impossible to change it.

I'm not trying to change anything, I just asking why... If the "why" is "just because", then maybe we're not improving the game to it's fullest.

There has been much discussion regarding the insane rates of fire today's marker can dish out paint. The advancement in marker research and developement is great. But we're still using the same paintballs this whole time. The only progress we've made has been in manufacturing techniques. How about some research into ball dynamics?

Did you know...

size ball vol. balls hopper volume
0.68 1.32 180 237
0.65 1.15 206 237
0.60 0.90 262 237
0.55 0.70 340 237
0.50 0.52 453 237
0.45 0.38 621 237
0.40 0.27 884 237

My Halo holds about 180 .68 balls. The same size hopper could hold 262 .60 balls!

[hitech]

There use to be .62 paintballs. They were lighter than the .68s. Some fields allowed a higher velocity (325 vs 300) for the smaller, lighter .62 paintball. Lighter is not desirable, even at the increased velocity. I believe they had less range.

Edit: fixed after reading Mike e's responce (.60 vs .62)

[mike e]

oh oh i know!

though back in the 80s .62 cal was available and remotly popular, .68 became the industry standard for several reasons. first and formost, tubing for barrels and bodies required far less machining to get to .68 as oppossed to taking the closest size to .62 and then reaming it to the correct diameter. furthermore paintballs were made from the same dyes as horse pills and bath beads I BELIEVE it might be one and not the other im not very positive on that one. but i do know that the technique for making paintballs is quite old. furthermore about the smaller paint going faster and hurting more, not quite true, you have to remember that "pain" as we would prolly interpet it from a paintball is caused by force. which is VxM i think. so a smaller mass going faster might not necessarily have the same force as a larger object going slightly slower, now i dont know the weight of the 40 cal or 62 cal paint available but if my memory serves me the velocities that the smaller paints were allowed to chrono at was only slightly higher then that of the larger counterparts, maybe 15-20fps or so. furthermore if anyone here has played airsoft those guns in some circumstances are allowed to chrono in over 400fps however, they are in no way near as "painful" as a paintball. also remember the smaller mass flying through the air is more subject to wind. seeing as how we are shooting rather light objects that are not known for flying straight in air anyway, i definatly would not want to sacrafice any more weight to make the things whip even more then they do. just my 2 cents im still in HS so i dont have any hardcore numbers to back this up but i will look for some shortly. i believe a debate similar to this came up on docsmachine not to long ago, perhaps manike or some of the other guild regulars could help clear up my poor feeble mind?

[manike]

Originally posted by hitech
There use to be .62 paintballs. They were lighter than the .68s. Some fields allowed a higher velocity (325 vs 300) for the smaller, lighter .62 paintball. Lighter is not desirable, even at the increased velocity. I believe they had less range.

Yep, I started playing back in the days when you could turn up and choose your calibre :)

.62 gave you more shots and could be chrono'd higher (can't remember if it was 320 or 340). I can kid myself that the chrono limits for .68 were 320 and .62 were 340, but I might be imagining it. I do remember there being different chrono limits back in the early days before it was all set at 300 as a nice round number (with a safety margin) and for consistency across events.

.68 was felt to give you more range and accuracy even back then and it wasn't long before .68 became the norm.

manike

[Jack & Coke]

My whole thing is this...

The origin of the .68 size is NOT base on paintball research. It is based on marking tree or cattle or horse stuff.

I think paintball has grown to the point that we don't have to reply on the sizes established for "non-paintball" reasons.

Given such variables as:

Velocity
Mass
Size

Is it possible to create a .65 paintball which would have the same IMPACT ENERGY, MOMENTUM and DISTANCE as a .68 ball?

What if... there were no such thing as "paintball" (blasphemy!) and you had start from scratch. What size ball would you use? Remember, you have a manufacture ready to make ANY size you want.

[Jack & Coke]

Can someone answer this:

What's the average DISTANCE of a tourney field from one end to the other?

What is the average WEIGHT of a paintball?

How HARD is the average shell?

What is the average IMPACT ENERGY of a .68 ball traveling at 300 fps at very close range (bunker move)?

Can anyone post actual test numbers (ahem... AGD are you reading this?)?

[manike]

Like with anything there is a trade off.

If you made bigger heavier balls they would travel more slowly and may even be easier to dodge, at some point the energy, mass, cross sectional area, desired angle of elevation, and velocity would trade off to find an 'optimum size'.

It's a calculation that with a bit of programming should reach a solution. But there are other variables which are not so easy to factor in.

It does depend on how fast you want the projectiles moving, and how high you want to aim. I don't think there would be any point going for more range if the balls travelled slowly enough to dodge and you had to point your gun up in the air :)

manike

[mykroft]

.50 and .40 were also available. IIRC .40 is what they use in China currently.

We inherited .68 from Cattle/Tree marking, and the other calibre's never took off.

There is no reason to replace .68 now, not with the amount of investment in design & manufacturing for the .68 calibre paintball. It's about as likely as any OS replacng windows on the desktop.

[manike]

Originally posted by Jack & Coke
What is the average WEIGHT of a paintball?

50-54 grains last time I checked (a few years ago now)

Originally posted by Jack & Coke
How HARD is the average shell?

Depends hugely on the brand and weather.

Originally posted by Jack & Coke
What is the average IMPACT ENERGY of a .68 ball traveling at 300 fps at very close range (bunker move)?

a 54 grain paintball at 300fps has 10.8ft*lbs of energy.

a 50 grain paintball at 300fps has 10 ft*lbs of energy.

Get the heavier paintballs

Jack & Coke did you read my long winded thread above which I snuck in when you were typing yours?

manike (not AGD but I hope my numbers help anyway )

[Jack & Coke]

Originally posted by mykroft
There is no reason to replace .68 now, not with the amount of investment in design & manufacturing for the .68 calibre paintball...

I said I'm not debating on whether or not we should change an industry standard.

I fully understand this. I'm just asking if .68 the BEST choice of ball size.

Plese ignore established manufacture and industry equipment for a minute. What size is best? go bigger? go smaller? Hard to believe .68 is the BEST. Heck, it's not even .68 anymore.... more like .689 or .69.

[Jack & Coke]

Thanks manike... I just read your post... I forgot to refresh my browser. I thought I was talking to myself...