Newbie may have had an epiphany - confirm or laugh

[xkjc]

Years ago, when I was in to archery, the big debate was carbon versus aluminum. We won’t get in to that, so let’s just say I was carbon. I was hunting and liked it fast and flat.

So I came across a spreadsheet I had done comparing a 270 to a 300 WM, I still like it fast and flat so the data is for a 130gr GMX vs. 168gr TTSX. Very similar BC and muz vel, so the ballistics are very similar. Obviously the 270 starts to give up KE quicker, losing about 20% to the 300 WM at 500y.

Then, recalling my archery days, the light went on (I think). The AL guys didn’t have to fight the wind, even if they were lobbing their arrows downrange. Me, a carbon guy, could use the same pin out to 40y, but was more challenged by the wind. I have been struggling with why fellas are shooting the heavier bullets and sacrificing a flatter trajectory. I had forgotten about my old friend MO.

So, let’s say KE is the ability to change something and MO is the ability to resist change. In focusing on fast and flat, I never wanted to sacrifice KE in hunting so I never went super light/fast. However, as I am learning more about the long range discipline and not necessarily hunting, I have recognized I have forgotten the value of MO.

With an LRF, distance is certain (or very nearly), so why am I so concerned about fast and flat? What’s a few more clicks, I’m going to dial anyways for a known and confirmed elev. dope. With a Kestrel or other, nearly everything in the equation is near certain and can be practiced for and repeated in. Except wind. Even with the Kestrel, wind is certain for a moment in time and a specific distance. Not over time, over distance.

I had been going fast and flat to cheat elev dope. Now I think I see why fellas are shooting the heavier bullets – to help with the uncertain wind vs saving a few clicks on the certain distance.

Did the newbie have an Ah Ha moment or is this an Uh Oh moment and I should just slither away now?

 

[Xdguy]

Re: Newbie may have had an epiphany - confirm or laugh

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: xkjc</div><div class="ubbcode-body">Years ago, when I was in to archery, the big debate was carbon versus aluminum. We won’t get in to that, so let’s just say I was carbon. I was hunting and liked it fast and flat.

So I came across a spreadsheet I had done comparing a 270 to a 300 WM, I still like it fast and flat so the data is for a 130gr GMX vs. 168gr TTSX. Very similar BC and muz vel, so the ballistics are very similar. Obviously the 270 starts to give up KE quicker, losing about 20% to the 300 WM at 500y.

Then, recalling my archery days, the light went on (I think). The AL guys didn’t have to fight the wind, even if they were lobbing their arrows downrange. Me, a carbon guy, could use the same pin out to 40y, but was more challenged by the wind. I have been struggling with why fellas are shooting the heavier bullets and sacrificing a flatter trajectory. I had forgotten about my old friend MO.

So, let’s say KE is the ability to change something and MO is the ability to resist change. In focusing on fast and flat, I never wanted to sacrifice KE in hunting so I never went super light/fast. However, as I am learning more about the long range discipline and not necessarily hunting, I have recognized I have forgotten the value of MO.

With an LRF, distance is certain (or very nearly), so why am I so concerned about fast and flat? What’s a few more clicks, I’m going to dial anyways for a known and confirmed elev. dope. With a Kestrel or other, nearly everything in the equation is near certain and can be practiced for and repeated in. Except wind. Even with the Kestrel, wind is certain for a moment in time and a specific distance. Not over time, over distance.

I had been going fast and flat to cheat elev dope. Now I think I see why fellas are shooting the heavier bullets – to help with the uncertain wind vs saving a few clicks on the certain distance.

Did the newbie have an Ah Ha moment or is this an Uh Oh moment and I should just slither away now?
</div></div>

From one Newbie to another, what you said makes plenty of sense to me. Then again, I am very very new to long range shooting.

 

[Powder_Burns]

Re: Newbie may have had an epiphany - confirm or laugh

Don't run down the street naked yelling 'Eureka!' but yeah, you are on the right track. Gravity's effect on your projectile is constant and predictable, while wind is chaotic at best. Lighter and faster for a flatter trajectory is an advantage when you are uncertain of the distance to the target...but its 2010 and we know the distance to our target or at least have a good estimation. The wind becomes an issue as you get further out, so the bullet that bucks the wind best is usually the most desirable.

 

[gcoulsey]

Re: Newbie may have had an epiphany - confirm or laugh

Man card introductory test: Complete

 

[TimK]

Re: Newbie may have had an epiphany - confirm or laugh

Your analysis is right on.

 

[ChadTRG42]

Re: Newbie may have had an epiphany - confirm or laugh

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: xkjc</div><div class="ubbcode-body">I had been going fast and flat to cheat elev dope. Now I think I see why fellas are shooting the heavier bullets – to help with the uncertain wind vs saving a few clicks on the certain distance.</div></div>
You got it right here. Wind is the big factor. And higher BC will help more in the wind and to retain more energy down range.

 

[Short-bus]

Re: Newbie may have had an epiphany - confirm or laugh

You aren't the only one that has had that same epiphany, I too had it at one time. I discovered that determining the distance to a target via LRF, or using a mildot master, or any other method, can get you a good range as long as you know how to use the tool. The problem is he wind. You can't see the air itself move, you have to depend on what it's moving to tell you what it's doing. Air is fluid, and doesn't move in straight lines. That being said, I can do distance, and range a target, but I couldn't tell you exactly what to do with the wind, and I shoot really heavy, really high BC bullets, to reduce my handicap in that area.

You're on the right track young grasshopper.

Branden

 

[RTH1800]

Re: Newbie may have had an epiphany - confirm or laugh

Makes you think of the .308 Win. at times?

 

[okiefired]

Re: Newbie may have had an epiphany - confirm or laugh

Yes, wind is THE ever present bitch. I have always prefered the heavies too (arrows also

) but another point to remember is, the bitch has more time to work on them than it does the lighter , faster bullets.

okie

 

[cdopson]

Re: Newbie may have had an epiphany - confirm or laugh

I once had the same epiphany. It was about the time I found this site. Imagine that. What you and I are is geographically challenged or we would've realized this a long time ago I would suspect.

 

[benjaminzero]

Re: Newbie may have had an epiphany - confirm or laugh

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: okiefired</div><div class="ubbcode-body">Yes, wind is THE ever present bitch. I have always prefered the heavies too (arrows also

) but another point to remember is, the bitch has more time to work on them than it does the lighter , faster bullets.

okie</div></div>


Time of flight/velocity is not the most important factor in wind drift. The ballistic coeficient of the bullet is. A slower velocity bullet with a high ballistic coeficient will have a benefit in the wind compared to a high velocity bullet with a poor ballistic coefficient. You might be able to launch a 155 amax alot faster than a 178 amax in a .308, but the slow heavy bullet will fare much better in the wind, even with a longer time of flight. Pushing a bullet faster will improve it's wind drift numbers, but further comparison is needed if you are talking about different bullets. This is more complex if you consider your rifle. With my 20" barrel, high BC, slow and heavy is best for the wind. I can't push a lighter bullet fast enough to compensate for it's low BC. A longer barreled rifle may be able, but it can push the "heavies" faster too.

 

[benjaminzero]

Re: Newbie may have had an epiphany - confirm or l

And remember, fast at the muzzle doesn't mean fast at the target. A bullet launched slower but with a much higher BC will catch up to that "fast" bullet because it retains more of it's velocity over time. Easiest way to test is using JBM and plugging different bullets and velocities. Great info, but moot if your rifle can't push those numbers or accuracy begins to suffer with that bullet weight or velocity.

 

[Short-bus]

Re: Newbie may have had an epiphany - confirm or laugh

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Zeroed1983</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: okiefired</div><div class="ubbcode-body">Yes, wind is THE ever present bitch. I have always prefered the heavies too (arrows also

) but another point to remember is, the bitch has more time to work on them than it does the lighter , faster bullets.

okie</div></div>


Time of flight/velocity is not the most important factor in wind drift. The ballistic coeficient of the bullet is. A slower velocity bullet with a high ballistic coeficient will have a benefit in the wind compared to a high velocity bullet with a poor ballistic coefficient. You might be able to launch a 155 amax alot faster than a 178 amax in a .308, but the slow heavy bullet will fare much better in the wind, even with a longer time of flight. Pushing a bullet faster will improve it's wind drift numbers, but further comparison is needed if you are talking about different bullets. This is more complex if you consider your rifle. With my 20" barrel, high BC, slow and heavy is best for the wind. I can't push a lighter bullet fast enough to compensate for it's low BC. A longer barreled rifle may be able, but it can push the "heavies" faster too. </div></div>

Okiefired, here's some comparisons;

Heavy and slow, 208 Amax @ 2450 vs. 155 Amax @ 2800, the 208 gets to 1000 yards .04 seconds sooner, with 3.2moa less wind deflection in 10mph full value wind.

Same with a 175smk @ 2650, 208 beats it to 1000 by .035 seconds, with 2.1moa less wind.

The only light bullet that fares well against the 208 is the 155 Scenar, which beats the 208 to 1000 by .1 seconds, but till requires 1.7moa more wind.

The heavies with really high BC's kill the lighter bullets in the wind, and depending on the bullet, still win out in the long race to the far target.

Like Zeroed said, time of flight isn't the big factor here, if it were, we would all be shooting the lightest bullet as fast as possible and there wouldn't be a manufacture making heavy bullets.

Branden

 

[karagias]

Re: Newbie may have had an epiphany - confirm or laugh

Seems like two ballistic coefficients are required to better characterize the performance of a bullet, one for normal fight (pointy end first) and another for sideways flight. It is possible that two bullets of equal caliber, weight, and normal flight BC could have different performance in the wind. It would be helpful if 90 degree BCs were published by bullet makers. This makes me wonder how difficult it would be do determine a value for a 90 degree BC experimentally.

 

[benjaminzero]

Re: Newbie may have had an epiphany - confirm or l

Chapter 5: Wind deflection

I can't even begin to explain the amount of info inside.

 

[vman]

Re: Newbie may have had an epiphany - confirm or l

F*** yeah !

 

[Greg Langelius *]

Re: Newbie may have had an epiphany - confirm or l

Time of flight rules.

The shorter time of flight will <span style="font-style: italic">always</span> deliver less drop and less wind drift. We achieve this with velocity and BC. Weight, bullet size, shape, etc., are all important only in as much as they affect BC and TOF.

Forget about 'sideways' BC's and any mysterious 'lifting forces' due to head/tailwinds. The only effect head/tailwinds have is the influence they have on TOF. A headwind extends TOF, thus producing more drop/drift and the opposite is also true of tailwinds.

Any angular deflection of the bullet axis from the line of the trajectory produces yaw (regardless of whether it's in the horizontal or vertical plane, for ballistic purposes it's termed 'yaw'), increases drag, and this results primarily in a reduction of effective BC. Thus TOF, Drop, and Drift increase over the optimally calculated values. Yes, there is also so off-axis deflection, but this is unpredictable and because of wobble and precession, much of it cancels out.

The more one learns, the simpler matters actually become.

Wind deflection can be likened to a cue ball.

Constant winds have an effect like adding (a small) tilt to the table.

Momentary gusts along the trajectory can be likened to 'thin slicing' collisions with object balls.

The sooner they occur and the longer they run, the larger their accumulated effect.

Greg

 

[okiefired]

Re: Newbie may have had an epiphany - confirm or laugh

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dust_Remover</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Zeroed1983</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: okiefired</div><div class="ubbcode-body">Yes, wind is THE ever present bitch. I have always prefered the heavies too (arrows also

) but another point to remember is, the bitch has more time to work on them than it does the lighter , faster bullets.

okie</div></div>


Time of flight/velocity is not the most important factor in wind drift. The ballistic coeficient of the bullet is. A slower velocity bullet with a high ballistic coeficient will have a benefit in the wind compared to a high velocity bullet with a poor ballistic coefficient. You might be able to launch a 155 amax alot faster than a 178 amax in a .308, but the slow heavy bullet will fare much better in the wind, even with a longer time of flight. Pushing a bullet faster will improve it's wind drift numbers, but further comparison is needed if you are talking about different bullets. This is more complex if you consider your rifle. With my 20" barrel, high BC, slow and heavy is best for the wind. I can't push a lighter bullet fast enough to compensate for it's low BC. A longer barreled rifle may be able, but it can push the "heavies" faster too. </div></div>

Okiefired, here's some comparisons;

Heavy and slow, 208 Amax @ 2450 vs. 155 Amax @ 2800, the 208 gets to 1000 yards .04 seconds sooner, with 3.2moa less wind deflection in 10mph full value wind.

Same with a 175smk @ 2650, 208 beats it to 1000 by .035 seconds, with 2.1moa less wind.

The only light bullet that fares well against the 208 is the 155 Scenar, which beats the 208 to 1000 by .1 seconds, but till requires 1.7moa more wind.

The heavies with really high BC's kill the lighter bullets in the wind, and depending on the bullet, still win out in the long race to the far target.

Like Zeroed said, time of flight isn't the big factor here, if it were, we would all be shooting the lightest bullet as fast as possible and there wouldn't be a manufacture making heavy bullets.

Branden </div></div>

Hey ...guys....like I said in my post, I run the heavies too, always have and for all the reasons already mentioned. I was just reminding the OP to consider all the facts. If I never shot over 300 yrds and mostly in calm winds, I might reconsider

. Good thread.

okie

 

[xkjc]

Re: Newbie may have had an epiphany - confirm or laugh

OP here. Thanks for all of the info and replies! I've been sitting back trying to digest it. There are many variables, but it does sound like maximizing velocity and BC is the consensus. Albeit since these are often juxtaposed I’ll need to run the numbers to see what trading one for the other does in different scenarios. If I understood most of the above, TOF is determined by velocity and drag (BC). Shorter TOF reduces the opportunity both gravity and wind have to affect change. BC is the aerodynamics of the bullet, how well it overcomes air resistance and maintains velocity and direction. The goal is to maximize both. OK, now off to JBM to learn some more with trade off examples…

 

[xkjc]

Re: Newbie may have had an epiphany - confirm or laugh

BTW, thanks Greg for the cue ball example. Simple and so noted – Wind at the shooter is most important.

 

[Greg Langelius *]

Re: Newbie may have had an epiphany - confirm or laugh

It's all too easy to get hung out on the 'more is better' limb.

Hypervelocity carries its own defects. For instance, it's tough on barrel throats, and most bullets have an upper speed limit due to centrifugal forces and copper fouling issues.

As one ages out of the population, some simple correlations begin to come together.

As long as drop and wind deflections are consistent and predictable, it's makes a lot of sense to stop going after the ultimate and start simply accepting and working with what one has, whatever it turns out to be. The only real limitation regarding velocity is that we want to stay above 1300fps out where the target is. As long as it's faster than transsonic, it really doesn't matter how much faster.

This is why I abandoned the .308 and favor of the .260. It uses the same capacity more efficiently, Yes, the .308 can do it, but it does it by leaping tall buildings, etc., out of the muzzle and it still ends up arriving out there kinda suckin' wind. There's also the matter of longer barrels. They can generate higher velocities, true; but if that's not your goal, they can also generate more sedate ones with less wear and tear on the internals.

Do yourself and your rifles a favor and give the master blaster syndrome a pass.

Greg

 

[Fuzzball]

Re: Newbie may have had an epiphany - confirm or laugh

"Newbie may have had an epiphany - confirm or laugh"

I didn't laugh but I did chuckle. Your "epiphany" is a well known fact.

 

[karagias]

Re: Newbie may have had an epiphany - confirm or laugh

I like Greg's approach to shooting, perhaps best characterized by serene and lucid yielding contentment and happiness. That's a smart way to live life.

But for me, I can't help thinking about a discarding-sabot, fin-stabilized tungsten dart that gets there now.

 

[Greg Langelius *]

Re: Newbie may have had an epiphany - confirm or laugh

My approach is actually quite pragmatic. It boils down to how much velocity one can pay for. Going fast is a matter of money, how much speed can you afford?

In my case, its a matter of getting as much as I can afford, and more is an unaffordable luxury. On the whole, ammunition components don't tend to cost out a lot different no matter how fast you go, within reasonable limits.

The real cost is in maintaining the rifle. My limiting factor is bore life. If lobbin' 'em, as apposed to laserin' 'em, will allow me to keep lobbin' 'em long after the laserin' is done due to bore expiration, then lobbin' 'em is my choice.

I have a really nice custom barrel, my first and only. It performs in a workmanlike manner, and I respect that performance by keeping the internal mayhem within limits. As it happens, it (an L-W 28" .260Rem) will lob a 142SMK at 2855fps-ish and it would probably pay to turn the wick down even on that, as right now, it arrives (on paper) at 1Kyd doing 1500fps. That's 200fps in excess of what's necessary. 2600fps is enough to get 'em ontarget at 1Kyd with 1300fps. I see <span style="font-style: italic">no</span> point in driving them any harder.

Now a 6.5-284 would probably outperform me. The issue is wind shooting. But we both have the same problem, and we both succeed or fail primarily on our ability to employ <span style="font-style: italic">our particular rifle's</span> drift characteristics.

In truth, we're doing the same thing; I just have to do a bit more of it. If my wind foo is greater, I win. Doing it with proper finesse, yet doing it with greater bore life, makes me what I consider to be the <span style="font-style: italic">real</span> winner.

Unfortunately, my current wind foo is at the (worn out and decrepit) grasshopper stage. Even grasshoppers get old...

Greg

 

[tuckner]

Re: Newbie may have had an epiphany - confirm or laugh

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Greg Langelius *</div><div class="ubbcode-body">

Wind deflection can be likened to a cue ball.

Constant winds have an effect like adding (a small) tilt to the table.

Momentary gusts along the trajectory can be likened to 'thin slicing' collisions with object balls.

The sooner they occur and the longer they run, the larger their accumulated effect.

Greg</div></div>

Awesome, I have understood this principal as I have been learning more about long range shooting, but this analogy cannot make it more clear and illustrative. I'm definitely going to be using this as I try to teach other people, and I wish I heard it from the get go.

Thanks Greg.

 

[Fuzzball]

Re: Newbie may have had an epiphany - confirm or laugh

It appears that most people think in terms of wind "drift", even some knowledgeable folks use that term. Of course a bullet will drift some during flight but that's a minor component what happens. The major component is "deflection". At the speeds a bullet is boring into the air any movement of that air deflects the bullet as surely as striking a series of twigs on the same side.

Wind drift only moves a bullet sideways a little, wind deflection litterly changes it's flight path/angle.

 

[sandwarrior]

Re: Newbie may have had an epiphany - confirm or laugh

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: gfunkUK</div><div class="ubbcode-body">Man card introductory test: Complete</div></div>

That's some funny shit right there! I wonder if they still issue ratings on those. You know, DA= dumbass, WT= won't talk, WSU= won't shut up.... Still all ya gotta do to get one is like man things and not worry about how your doilies came through the wash.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Fuzzball</div><div class="ubbcode-body">It appears that most people think in terms of wind "drift", even some knowledgeable folks use that term. Of course a bullet will drift some during flight but that's a minor component what happens. The major component is "deflection". At the speeds a bullet is boring into the air any movement of that air deflects the bullet as surely as striking a series of twigs on the same side.

Wind drift only moves a bullet sideways a little, wind deflection litterly changes it's flight path/angle.

</div></div>

You make it sound as though some little brownie was in there pushing on the rudder pedals.



A big bullet flying through the air has a given energy set on a given vector. Assuming the stability of the bullet, that will continue on a predictable downgrade until the bullet decreases in velocity enough to reach the transonic range. Same with the smaller bullet.
The smaller bullet starts with a smaller energy and degrades in energy faster.
As an example I use two different bullets from the same caliber, a 120 Sierra and a 168 SMK in 7mm pushed respectively out at 3030 and 2730 fps.
At 200 yds. the 168 has drifted 2.8" has an energy of 2103 and TOF is .235. The 120 gr. bullet moved 3.8" energy of 1623 and TOF of .219
At 400 yds. the 168 has been in the air .502 seconds, and been blown by a 10 mph wind 12.2 in. The same 120 gr. bullet has been blown 17 in. But, has only been in the air .492 seconds. The energy is 1554 to 1031.
At 600 the 168 has moved over 29.8" and the 120 43". TOF now favors the 168, .827 to .836 The energy difference is the key 1120 to 633.
The results from 800 and 1000 move further still in the 168's favor.
The loads I used were two of the hotter ones I could get from my 7mm-08.

My bottom line is BC = retained energy which helps the bullet stay on course. Had the bullets simply flowed with the wind over time of flight, the 120 gr. bullet would have drifted 36" @ 200. The 168 would have drifted 44". The the imparted energy given to a bullet and what it retains has a lot more bearing on drift than does time of flight.

 

[Greg Langelius *]

Re: Newbie may have had an epiphany - confirm or laugh

The way to consider the effects of wind is to imagine the bullet being fired the length of a huge moving boxcar, essentially with dimensions big enough to contain the entire trajectory, filled with something the consistency of jello.

This is a huge exaggeration, but the concepts are the same.

If the boxcar is moving relative to the rifle, differences in its motion will have varying effects on the bullet's path.

If the boxcar is moving toward the rifle, the bullet will be slowed more; and if it's moving away, it will be slowed less. Motions of the boxcar up/down, left/right, will likewise alter the bullet's path at an angle to the initial projected POI.

The way to think is to consider inputs and outcomes. Altering the inputs alters the outcomes. The bullet's path alters to conform to the motions of whatever medium it flies through.

Greg

PS, Regarding the drift vs deflection terminology, I use the words as I was taught, and sometimes the meanings are a little skewed. Please appreciate that not a lot of the folks who taught me were college toffs. It occasionally arouses the terminology nazis...

 

[sandwarrior]

Re: Newbie may have had an epiphany - confirm or laugh

Greg,

I use the two words interchangeably when considering bullet flight path.

I do not use the word drift in reference to angle of impingement of the oncoming wind as it strikes (is struck by) the bullet while in flight. Meaning if a bullet is moving forward, parallel to the ground, yet the nose is pointed up or sideways, the ensuing deflection will alter the course of the bullet. An example would be at the end of flight of a long shot the bullet would want to remain nose up in relation to the bullets now downward flight path. Gyroscopic forces want it to stay in line with the barrel it was fired from. Or as a bullet enters the transonic range and is disrupted by the shock waves leaving off the bullet. The gyroscopic precession wants to move the nose of the bullet 90 deg. from the point at which the shock force was introduced. Causing the oncoming air to strike the bullet not on the tip but on the ogive.

For all intents and purposes to me, deflection need not be a part of this discussion. Drift would be an adequate description for this discussion. Any deflection due to wind can be accounted for in the drift of a bullet in stable flight.

Edit:

FWIW, I'm in agreement with you on the choice of caliber/speed issue. The only thing I differ with you is TOF. My comparison though is a 120 and a 168 gr. 7mm bullet. Another comparison I used is the 175 SMK and 142 SMK at 2660 and 2800. Those two bullets, at those speeds, literally stay hand in hand out to 1k.

 

[Greg Langelius *]

Re: Newbie may have had an epiphany - confirm or laugh

We have no dispute. I learned long ago that what computes is not always the same as what shoots. There is sufficient wiggle room for seemingly dissimilar concepts and principles to deliver concurrent outcomes.

...Or as a friend once told me, "There be many ways to defur the domestic feline, Sonny jim...".

Greg

 

[azimutha]

Re: Newbie may have had an epiphany - confirm or laugh

At some point, there will be a bullet that exceeds the ability of the barrel twist to stabilize it and increased weight means increased recoil. That may be a factor, depending on how you handle it.

 

[sandwarrior]

Re: Newbie may have had an epiphany - confirm or laugh

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: azimutha</div><div class="ubbcode-body">At some point, there will be a bullet that exceeds the ability of the barrel twist to stabilize it and increased weight means increased recoil. That may be a factor, depending on how you handle it.</div></div>

I think in this case it's a given the rifle selected will be capable of handling both.