What caliber for a sheep rifle?

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BJlooper,

WHAT????

Did you just say what I think you said, BC has nothing to do with wind drift, only time of flight????

I must have read that wrong.

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KirbyYou did not read my post wrong. I base my statement on Physics alone. When a bullet leaves a barrel it drifts at the velocity of the air that it is taveling in. Reguardless of weight, or shape. The distance it drifts is equal to time time velocity (D= T x Vw). The affect that BC has on Drift is olny in how it affects time of flight.
If you know of any other lateral forces that act on the bullet during it's flight ( excluding the rotation of the earth, to small to be considred in this case) please explain them to Sir Isaac Newton and me.

Anidotal evidence doesn't change the laws of Physics. When you shoot your rifles you only know the velocty of the wind atthe rifle. Who knows what the vlocity is at 100yd or 500yd. It might even change direction along the bullets path.

DR B
 
[ QUOTE ]
[ QUOTE ]
BJlooper,

WHAT????

Did you just say what I think you said, BC has nothing to do with wind drift, only time of flight????

I must have read that wrong.

[/ QUOTE ]

KirbyYou did not read my post wrong. I base my statement on Physics alone. When a bullet leaves a barrel it drifts at the velocity of the air that it is taveling in. Reguardless of weight, or shape. The distance it drifts is equal to time time velocity (D= T x Vw). The affect that BC has on Drift is olny in how it affects time of flight.
If you know of any other lateral forces that act on the bullet during it's flight ( excluding the rotation of the earth, to small to be considred in this case) please explain them to Sir Isaac Newton and me.

Anidotal evidence doesn't change the laws of Physics. When you shoot your rifles you only know the velocty of the wind atthe rifle. Who knows what the vlocity is at 100yd or 500yd. It might even change direction along the bullets path.

DR B

[/ QUOTE ]
I could not agree with Fiftydriver more "BJLooper,WHAT ????" you and Sir Isaac Newton need to invest in a ballistic program (Sierra Infinity,Exbal etc.) you are really off base on this one.
UB
 
Bjlooper,

Well my friend we will have to agree to disagree. Obviously you appear to be more indepth about the physics part of things at least on paper but I can not and will never agree with your comments because most of what physics is is testing an idea in real life conditions and in real life conditions your statements are incorrect.

Have you had trouble hitting targets at long range before?

Also, you must believe that every one of the ballistic programs on the market today are giving us incorrect ballistic data because everyone will tell you a slower bullet with a large BC advantage will have less wind drift then any high velocity low BC bullet at extended ranges.

As I said, we will agree to disagree as it seems you are set on your comments which is fine with me.

Just before you start throwing bullets at big game at long range, please test your theory on paper at long range just for the sake of respecting the animals you are shooting at.

Good Shooting!!!

Kirby Allen(50)
 
Dr. B,

Your observation is somewhat correct, but incomplete. A bullet with a high BC has a more aerodynamic anterior and lateral surface. This shape minimizes the amount of atmospheric force that may be encountered from either the front or sides.

As for explaining this to Sir Isaac, he did all of the research and experimentation necessary to prove his theories (at least until the time of Einstein)
Actually, it took Newton some time to clarify the concept of force, which had previously been unclear. This is discussed at length in Never at Rest, by Richard Westfall

To put it in his own words (although actually he wrote it in Latin, this is from an 1803 translation):

"If a body impinge upon another, and by its force change the motion of the other, that body also" (because of the equality of the mutual pressure) "will undergo an equal change, in its own motion, towards the contrary part. The changes made by these actions are equal, not in the velocities but in the motions of bodies; that is to say, if the bodies are not hindered by any other impediments. For, because the motions are equally changed, the changes of the velocities made towards contrary parts are reciprocally proportional to the bodies. This law takes place also in attractions."

This should clarify some of the confusion by illustrating that the lateral velocity of movement is lower in a high BC bullet, resulting in lesser distance in wind drift; as proven by your point (D= T x Vw).

I hope I haven't been offensive or derogatory toward you in any personal manner. I enjoy these controversial topics and the friendly debates that ensue from them. Your points are very astute and give me a challenge to ponder; therefore I learn a little bit more about ballistics and LR hunting from this. All of the intricate details involved in LR accuracy continues to increase my appreciation for your talent.

Dave
 
[ QUOTE ]


KirbyYou did not read my post wrong. I base my statement on Physics alone. When a bullet leaves a barrel it drifts at the velocity of the air that it is taveling in. Reguardless of weight, or shape. The distance it drifts is equal to time time velocity (D= T x Vw). The affect that BC has on Drift is olny in how it affects time of flight.
If you know of any other lateral forces that act on the bullet during it's flight ( excluding the rotation of the earth, to small to be considred in this case) please explain them to Sir Isaac Newton and me.

Anidotal evidence doesn't change the laws of Physics. When you shoot your rifles you only know the velocty of the wind atthe rifle. Who knows what the vlocity is at 100yd or 500yd. It might even change direction along the bullets path.

DR B

[/ QUOTE ]

DR B,

If what you say is correct, then those big three masted sailing ships of the past could have gotten by with a single mast and one small sail!

Any sailor will tell you that the shape and the angle of attack of the sail to the wind will determine how efficient the ship will be!

The sails and their angle are very similar to the shape of the bullet, IMO.....I have a page in to Sir Isaac, but he is not answering /ubbthreads/images/graemlins/wink.gif

edge.
 
****!!!!! Now I've got to sell about 500# of heavy bullets and get me some little bitty ones. /ubbthreads/images/graemlins/tongue.gif /ubbthreads/images/graemlins/shocked.gif /ubbthreads/images/graemlins/tongue.gif

Sure wish I'd have know this a looong time ago. Here all these years I've been shooting the wrong booolits. /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/smile.gif /ubbthreads/images/graemlins/grin.gif

All of the testing and long range shooting and comparison not only with multiple software programs but years of field experience and playing and testing have all been wasted. /ubbthreads/images/graemlins/shocked.gif

I'm tired of switching so I think I'll just stick with the heavy, slow, long in flight bullets since my feeble little mind seems to think that thousands of rounds, in the field, and a lot of dead animals, have proven the heavy for caliber, high BC bullets have ALWAYS proven to be better in the wind and at long range than any light weight speedster ever. /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/smile.gif /ubbthreads/images/graemlins/grin.gif

[ QUOTE ]
Anidotal evidence doesn't change the laws of Physics. When you shoot your rifles you only know the velocty of the wind atthe rifle. Who knows what the vlocity is at 100yd or 500yd. It might even change direction along the bullets path.

[/ QUOTE ]
Exactly, Thats what the high BC bullets are used for, at least by some of us.

As a disclaimer: I base my statements on field experience alone, no physics, on everything from rocks to bull elk, and at ranges from about 25 yards to 2000 yards. I've tried and tried but my cases are so full of powder and those pesky, heavy for caliber, high BC bullets, that I've never been able to squeeze any physics in along with the powder. /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif
 
Man I need to step back and put on my Red and Green stripped socks OVER my OD green one this is getting deep!!

Anyway , My choiche would probably be narrowed down to the 7mmWSM in a SA Rem 700 with a 24" either light conture #2-3 barrel or one of ABS carbone units depending on the funds available. Bedd all that into a HighTech stock or one of the new carbon ones that Kirby is using (forgot the name).
top it off with a Good scope in the 3-10x40mm class and mount it in a set of Tally's one piece base/ring sets.
this should give to a rig in the 7-8lb class and still be an effective 500yd gun.
now in the funds are free then buy one of the NULA actions wigh is about 1/2-3/4lb lighter than the R700 and use one of the Carbon tubes
 
[ QUOTE ]
When a bullet leaves a barrel it drifts at the velocity of the air that it is taveling in. Reguardless of weight, or shape. The distance it drifts is equal to time time velocity (D= T x Vw).

[/ QUOTE ]

.....well part of the confusion might be arising from the first part of that:
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it drifts at the velocity of the air that it is taveling in

[/ QUOTE ] ....er, no. It is accelerated by the force exerted on it by the air it is travelling in.....a bullet leaving a muzzle in a 10mph crosswind doesn't immediately go sideways at 10mph!

...how fast is it accelerated? Well that will be a function of it's BC. ...but not its 'quoted' BC; because that only quantifies the effect of its shape steadiness etc 'nose-on' .....to be accurate you would have to assess its BC relative to the wind direction (ie for a 90deg wind the bullet is essentially flying sideways) no one would argue that a bullet with a BC of 0.5 would still be a 0.5 BC bullet if it was fired base first; the same is true if it were fired sideways.

....so, (and if I'm making no sense here, it's because I'm typing this with a wee bit of a hangover /ubbthreads/images/graemlins/crazy.gif) bjlooper is partly right; the 'nose on' BC is not, strictly speaking, relevant when calculating wind drift (because you would actually need the bullet's 'side on' BC for that particular wind angle).

...the fact that the ballistic programs are indicating reduced winddrift due to higher BC is not proof; unless the program in use is 'fudging' an assumed lateral BC based on, say, a calculation involving the BC of a sideways presented 'standard bullet' (they're all essentially similar bullet-diameter tubes when side on) and the actual bullet's nose on BC.

.....I would suspect that the empirical 'heavy bullets drift less' observations have much to do with the inertia of the greater mass.

Hope I've confused everyone /ubbthreads/images/graemlins/smile.gif /ubbthreads/images/graemlins/confused.gif
 
Brown dog,

Taking your comments, especially your last one, look at this example please. Lets compare two bullets, the 200 gr Accubond with the 220 gr Hornady round nose. Using a BC of .58 for the Accubond and .3 for the Hornady bullet, both launched at 3000 fps.

At 500 yards the Round nose will drift over 32" compared to about 14.5" for the 200 gr Accubond. The Hornady bullet will have more momentum then the lighter 200 gr bullet when started at the same velocity so why is the wind drift more then twice that of the lighter 200 gr Accubond. Simply put, higher BC.

Now I am sure that the physics guys and gals can figure up an equation on this to tell us why this happens but personally, simply knowing a higher BC bullet will produce less wind drift then a high BC bullet is enough for me.

It happens in real life all the time and in every caliber with every bullet weight. A higher BC will produce less wind drift then a lower BC bullet.

This is an interesting topic but to be honest, it kind of baffles me that it is getting this much attention on this board. This is kind of a LRshooting 101 type topic in my opinion. The math can get very complicated but the results are very predictable.

Good SHooting!!

Kirby Allen(50)
 
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Brown dog,

Taking your comments, especially your last one, look at this example please. Lets compare two bullets, the 200 gr Accubond with the 220 gr Hornady round nose. Using a BC of .58 for the Accubond and .3 for the Hornady bullet, both launched at 3000 fps.

At 500 yards the Round nose will drift over 32" compared to about 14.5" for the 200 gr Accubond.

[/ QUOTE ]

Kirby
the time of flight of the 200 gr Accubond is less than the 220gr round nose.

Dr B
 
Kirby, BjLooper

I don't think TOF differences account for the almost 100% difference in Kirby's computer predicted drift....the roundnose would take about 14% longer to get to the target; but intuitively that isn't enough to double computer predicted drift

...I would suspect that the ballistic programs we're using are not considering the 'side aspect BC' of the bullets at all and so computer predicted drift is artificially exagerated in favour of the bullet with the best nose-on BC...

...I think it likely that the 'side aspect BC' of these 2 bullets is probably very similar....and that they would therefore undergo similar lateral accelerations.....albeit the roundnose for 14% longer.

It'd be interesting to learn how much the difference was if the 2 rounds were actually fired under those conditions. I would expect the roundnose to have more drift, but not the computer predicted 'double value' drift.

(but, I don't think any of us will be running out to do the test! /ubbthreads/images/graemlins/smile.gif...I'm trying to pack my kit ready to fly up to Scotland tomorrow for a couple of days stalking /ubbthreads/images/graemlins/cool.gif).

All the best

Matt

PS. Kirby; have you ever exported any of your work to the UK?
 
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