Tiberius Sniper Rounds, Info from TK

[mostpeople]

Oh, i trust math, but math doesnt guarantee that is the correct drag coefficient to use. Estimating drag coefficient by the general bullet shape of the "sniper round" is not sufficient. The bullet shape coefficient does not account for spin, the fins, the hollow back side of the round, and many other details. You could estimate a golf ball by using a sphere, but then you would use the wrong drag coefficient and results would be way off. I trust concrete, repeatable results more than any estimate.

Mathematically, without the drag coefficient, any calculation done is an estimate. You cant disprove something with an estimate.

Ahh and I agree with you, thats why I labeled it a hipshot, an estimate, an argument for a reason why they MIGHT not perfrom the way they are advertised.

My goal of the post is to get some serious testing on these things because, well obviously - I am skeptical

As far as the coefficient, its going to be higher than a sphere, that is garaunteed, the issue is the laminar flow behind the ball, which, obviously doesn't exist with the shroud. The hollow backside will make it more turbulent, and the spin with friction ignored will not affect the drag. The fins, will only cause more drag, which is the issue I am getting at.

[cockerpunk]

Ahh and I agree with you, thats why I labeled it a hipshot, an estimate, an argument for a reason why they MIGHT not perfrom the way they are advertised.

My goal of the post is to get some serious testing on these things because, well obviously - I am skeptical

As far as the coefficient, its going to be higher than a sphere, that is garaunteed, the issue is the laminar flow behind the ball, which, obviously doesn't exist with the shroud. The hollow backside will make it more turbulent, and the spin with friction ignored will not affect the drag. The fins, will only cause more drag, which is the issue I am getting at.

without doing the CFD myself, im gonna say that the shape has A LOT less drag then a sphere. and it has two very good stabilizing factors on top of the less drag. i can't really see a reason why it doesn't work. its based off the fn 303, a millitary/para milliray weapon, so i dont see a reason why it shouldn't work.

i for one think it works, but im very interested in sticking this thing under our new highspeed camera and seeing what it looks like at 1200 fps.

[mostpeople]

without doing the CFD myself, im gonna say that the shape has A LOT less drag then a sphere. and it has two very good stabilizing factors on top of the less drag. i can't really see a reason why it doesn't work. its based off the fn 303, a millitary/para milliray weapon, so i dont see a reason why it shouldn't work.

i for one think it works, but im very interested in sticking this thing under our new highspeed camera and seeing what it looks like at 1200 fps.

nah dude, it has more drag.. more surface area exposed to the axial flow

[cockerpunk]

nah dude, it has more drag.. more surface area exposed to the axial flow

its all in the way the boundary layer effects the drag shape

[mostpeople]

well right, thats what im saying, at that high speed/reynolds number.. the flow is laminar, with little turbulence on the backend.. meaning its very aerodynamic

[cockerpunk]

well right, thats what im saying, at that high speed/reynolds number.. the flow is laminar, with little turbulence on the backend.. meaning its very aerodynamic

now i have no idea what your talking about. your tossing out terms without knowing what they mean. and now you say its more aerodynamic? im just confused here.

[mostpeople]

now i have no idea what your talking about. your tossing out terms without knowing what they mean. and now you say its more aerodynamic? im just confused here.

I am an aerospace engineering major, a drunk one at that! haha

But I digress..

basically the flow follows the contour of the ball past the apex or center on top and bottom of the ball towards the back, do you have aim? hit me up name = m0stpeople

[rx2]

i disagree.

at 50 feet we saw a CEP of about 2.5 inch radius.

thats more accurate then anyone i know can shoot.

So a clamped-down shot group of a 5-inch diameter, from 50 feet? If so, that is still pretty imprecise. As you say, most people can't shoot that with a pistol. Now, imagine if they had to shoot with a pistol as imprecise as that.

I have shot 5-inch groups, standing, from the 50, with my issued G17 with extra-heavy trigger and crappy 3-dot night sights. It is by no means a target pistol. Still, though, if you clamp it down, you are going to get a 1-inch group - much more precise than 5 inches. This basically assures that, where I am aiming, the round should go (at 50 feet). So, despite being a very good shot, I still amplify the imprecision of the pistol significantly. If you handed me a gun that was, at best, capable of a 5-inch group, I would probably be shooting 15-inch groups (maybe worse). To make matters worse, I couldn't realistically expect every shot to go where I was aiming, thus exacerbating the problem. When you only have a 5-inch target to hit, that is fairly significant.

Perhaps I am being too critical, but by my frame of reference, 5-inches is still pretty poor, especially considering the controlled environment. None the less, that is better than I had expected. As such, MANN's suspicion of 2-3x peak improvement seems much better founded. I wonder how they are measuring that they would come up with the 25x figure.

I don't mean to sound contentious. You do very good work, and I trust your results. I look forward to seeing the results that you (and others) get with these rounds.

[cockerpunk]

So a clamped-down shot group of a 5-inch diameter, from 50 feet? If so, that is still pretty imprecise. As you say, most people can't shoot that with a pistol. Now, imagine if they had to shoot with a pistol as imprecise as that.

I have shot 5-inch groups, standing, from the 50, with my issued G17 with extra-heavy trigger and crappy 3-dot night sights. It is by no means a target pistol. Still, though, if you clamp it down, you are going to get a 1-inch group - much more precise than 5 inches. This basically assures that, where I am aiming, the round should go (at 50 feet). So, despite being a very good shot, I still amplify the imprecision of the pistol significantly. If you handed me a gun that was, at best, capable of a 5-inch group, I would probably be shooting 15-inch groups (maybe worse). To make matters worse, I couldn't realistically expect every shot to go where I was aiming, thus exacerbating the problem. When you only have a 5-inch target to hit, that is fairly significant.

Perhaps I am being too critical, but by my frame of reference, 5-inches is still pretty poor, especially considering the controlled environment. None the less, that is better than I had expected. As such, MANN's suspicion of 2-3x peak improvement seems much better founded. I wonder how they are measuring that they would come up with the 25x figure.

I don't mean to sound contentious. You do very good work, and I trust your results. I look forward to seeing the results that you (and others) get with these rounds.

i have missed alot of shots at 50 by more then 2.5 inches, so to me that means my gun is more accurate then me. to me that means the issue is with me, and not my equipment.

really, its agreeing with MANNs post, if we are are already missing by larger margins then our equipment performs at, then what is the point of increasing the repeatability of our equipment?

[malJohann]

What would be really cool is if you could switch your T9 between feeding from the hopper or feeding from the magazine via an external lever combined with your newly converted magazine which is crammed with 8 First Strike rounds.

[MANN]

at 80' you can get 6"X9" grouping with 25 shots. testing was done with an Xmag, .684 Titanium Paintball barrel (alum series), and draxxus Xball gold paint.

For the cost I am not sure that the distance advantage is going to be worth it. With the accuracy I am not sure that there is going to be a huge advantage. Espicially after you factor in the fact that you still point and shoot these markers. Putting a scope on a paintball gun, and then rolling around in the woods with it is not going to stay "sighted in".

[Swamp Thing]

T9

You can have a T-9 feed off the clip and off a hopper. All you have to do is rotate the barrel

Swamp

[malJohann]

You can have a T-9 feed off the clip and off a hopper. All you have to do is rotate the barrel

Swamp

How quick can that be done in the field?

[Papa Smoke]

However long it takes you to turn your barrel 1/3 of a turn. T9s have a twist lock barrel.

[Spider-TW]

at 80' you can get 6"X9" grouping with 25 shots. testing was done with an Xmag, .684 Titanium Paintball barrel (alum series), and draxxus Xball gold paint.

For the cost I am not sure that the distance advantage is going to be worth it. With the accuracy I am not sure that there is going to be a huge advantage. Espicially after you factor in the fact that you still point and shoot these markers. Putting a scope on a paintball gun, and then rolling around in the woods with it is not going to stay "sighted in".

Your sight distance is less than 100 ft. A daisy point sight can hold that well enough for conventional paint. Anyone willing to crawl all day will probably spend more on their sight anyway.

mostpeople's (drunken ) argument neglects spin altogether, which has a significant effect, as observed in baseball, golf, and paintball. Fins make that spin controlled. Mass only affects sectional density of the projectile and the total energy in the round. The density in the Reynolds number is the fluid density. There is no mass of the object involved. The spin creates a 'let down' pattern at the back of the round, eliminating a lot of the turbulence and allowing a more stable flight.

Iirc, the original point of Perfect Circle was a seamless and consistent paint ball, well beyond the product of the time and unfortunately still far ahead of most paint delivered today. At the terminal target range of 80 ft, I can see bringing a spread in from 54 square in to 2 square in. We're talking about SKS accuracy (~4 minutes of angle).

I don't doubt it will fly right, but I'm with Doc Zox; it's not enough to make me buy a tiberius yet and I will be looking for something else to try them out on.

btw, high reynolds numbers are turbulent, low numbers are laminar, the dip inbetween is transitional.