Yah POP, I have other relatives that live near afton Wyoming and hunt out on the deserts of Wyoming for antelope and take some seriously long shots. I know you have posted before about you trying the 140 grain hornady boat tails in your .270. These will have a pretty good BC, but the accubonds may be better as well as the 150 grain ballistic tips (I personally wouldn't use the BTs on elk). But heck, you really aren't gaining a lot. For the open range deer shots i would like a 7 STW or 7MM WSM and shoot the new 175 grain matchkings or the like. I know, you may spit on me for saying that, but the poeple that have used both the BTs and the matchkings like the matchkings better and say they hold up better (hope I didn't ruin your post by stating this). The BCs of the 175 MKs are outstanding at .608 at the higher speeds! Guys at longrangehunting.com also use the berger VLDs for hunting, and for the heavier bullets in 7MM you are getting close to .7!

Velocity is secondary to me. If you look at my favorite load page you will see that very few of my loads are at max or over max...but the all print less than 0.5", 5-shot, 200-yard groups.

And you have obviously never read my main reloading page...

BC does matter to me as a target and varmint shooter. That's why I avoid the hollow point bullets made for expansion. Not that they don't shoot the best when the distance is moderate.

Today there are many plastic tipped bullets that have really improved this area. This is where my interest lies. For target shooting I am still using some lead tipped bullets as I load single shot and the meplats don't get banged up that way.

There was a magazine article that listed actual tests of BC's and almost all of the actual numbers were lower than what's published.

Just run the numbers on say a 70 gr 6mm bullet with a plastic tip vrs the old style HP 75 gr bullets and it's a miss on a varmint when there is wind.

That's some good advice Jon.

On a scale of 1 to 10 I'd rate BC about a -400.

Things that affect long range accuracy are of little importance to someone who usually shoots 30 yds.

Because when I buy bullets I buy them by the tens-of-thousands...and I have found that the HPBT bullets are generally the most accurate in most firearms.

And, when I load, I load for accuracy...

Yes, I'm familiar with how it's tested in real world. But I don't use standard load sets, what ever that is. I just use two separate chronographs placed some distance apart. I shoot through both of them, measuring the velocity of the same bullet at two distances. The procedure is repeated until I reach statistical significance . The MV differs too much between different rounds to make a standard load set approach reliable. Back at home I run the bullet velocity data in a program written in a language you probably wouldn't understand. There are probably english ones as well.

Ooh, Sorry DKing! At first glance it looked as if you adressed your post to me.

Sectional Density is my main criteria in a hunting bullet, many try to pass SD with BC and although they are somewhat related by their very nature, it cannot be done....

Very true. SD should be a much bigger concern in a hunting situation in my opinion.

I agree, but SD is part of what makes a BC. When I began playing around with 196 grn millsurp bullets in an 8X57, I was amazed at how little they dropped at near 300 yds @ only 2500 fs. If you havent seen them, they are a very sleek and streamline bullet. I am of the opinion that accurate BC testing and factual data is not very cost effective for manufacturers to develope and thus a lot of guestimation is involved in assigning said numbers. In other words, under certian circumstances, a very sleek bullet may just offer a little more than what the (inconsistent) data says.



But still, for the most part Im in agreement with most here and dont get excited about BC's beyond "what is the drop of this RN going to be" and "does this bullet have enough SD for the job". But I must admit, I do like what the bonded poly tipped bullets have to offer, especially the heavy for caliber ones that have more weight to drive those BEAUTIFULL pancaked mushrooms!!!

Olimahtes

Not a problem, I just picked your post to reply to Pop on.

What I mean by a standard set is 10 rounds loaded to the same specs. I only have one chronometer so I shoot 5 across at close to muzzle and 5 across at distance. I average the close and distant speeds and figure the generate a BC based on that set of 5 rounds average. I'm a simple kinda guy and this is just a check for me in cases where a BC looks exagerated.

Pop,
I'm with ricciardelli on this one. The bullets I use in my varmint rifles happen to have a high BC, but I use them because they are more accurate, not because of the BC.

In my hunting rifles, BC doesn't mean much to me. If the bullet I use has a high BC, I'll take it, but it doesn't mean a whole lot when shooting at medium size game, even at long range.

I ran a ballistic program just for grins for my 7-08AI and compared Nosler Ballistic Tips with a published BC of .485 with Swift A-Frames that have a published BC of only .335. This is at a modest muzzle velocity of only 2900fps from a 22" barrel. At 400 yards there is a difference, but who cares? I'll be shooting about 2.5" lower with the Swift at 400 yards. There will also be about 6" difference in wind drift at 400 yards. The way I look at it, if I can settle into a solid enough position to make a 400 yard shot on live game (without my bench), I can also adjust for the difference in holdover and windage. If I can aim 16" high, I can hold 18.5" high. If I can hold for 11" of drift, I can hold for 17" of drift. I'm more concerned if I can even take the shot. It's pretty difficult to hold a steady sight picture at 400 yards in the field. Even then, the game must be standing, and I must be able to accurately dope the wind. If I can do all that, adjusting the point of aim is the easiest part of the puzzle. All that matters then, is the performance of the bullet.

The answer to your qwuestion is a definite "IT DEPENDS". My two whitetail guns are a Whitworth Mauser 308 and a Remington VSL 7-08. I shoot 150 PPoints (poor BC) out of the 308. I use it when shots are to be generally ubder 150yds, but the bullet performs perfectly. I use Poly tipped (high BC) 140gn bullets out of the 7-08. It shoots flatter and carries the same energy to 300+yards. Of course if I changed bullet types it would be the same. capt david

Apart from the advantage high BC has over lesser BC in reduced wind drift and flatter trajectory, there is also the shorter time of flight. If an animal spooks or moves at the moment the shot breaks, shorter time of flight could be the difference between tracking and skinning. Looking at wind drift, trajectory and time of flight in isolation, each has a small effect. Together, they make a big difference and any advantage, however small, remains an advantage.

The Schultz twins.

In many rounds there is a trade off between the length of a high BC bullet and case capacity. A semi-spitzer can save quite a few grains of case capacity, and once you get an extra 100 fps, the high BC has less advantage. It takes a lot of distance for a bullet with a 20% higher BC to catch up, and terminal performance may notbe as good as the lower BC bullet.

Lack of case capacity can usually be overcome by going to a slightly faster powder or using a similar or slower burning ball powder instead of extruded powder and so on.

Taking three theoretical 150gr .308 caliber bullets with BCs of .50 .40 and .30 and shooting them at 2900fps, 3000fps and 3100fps will result in trajectories within half an inch of one another to 500 metres. Despite the similar trajectories resistance to wind drift of the higher BC bullets are far superior all the way to 500. The faster bullets give shorter time of flight in the mid range and the high BC bullets are quicker to 500.

You are right in that a lot of BC is needed to make up for just a 100fps of lost speed.

The bottom line is that a balance of highest BC combined with the highest speed remains first prize for getting the bullet as close as possible to the intended point of impact.

This is a fine line to tread and one that often takes a lot of actual shooting to discover the best combination.

Well said, Gina.

Quote:

---

And you have obviously never read my main reloading page...

---

I�m sorry, I didn�t realize it was required reading. I guess if it contains the meaning of life I�m SOL, eh?

Quote:

---

...but the all print less than 0.5", 5-shot, 200-yard groups.

---

No doubt that�s impressive. But what is it good for with a big game rifle? What does one hunt with a big game rifle that is so small that sort of accuracy will give you any meaningful advantage at 200 yards over a rifle that shoots groups three times that size? The Mystical Mouse Deer?

It�s at ranges much farther where that sort of accuracy makes a meaningful difference when hunting big game. So if one can shoot tiny groups at 100 and 200 yards, but does so with bullets that don�t do so well in realistic conditions at ranges where accuracy is useful, what has he accomplished? In my opinion, nothing.

I�ll choose the bullet that shoots the best under those conditions at ranges beyond those at which I intend to hunt every time. I don�t care if another bullet shoots .0001� groups at 100 or 200 yds. If a light breeze means I can�t hold significantly less than 1 MOA at 400, 500+ etc, it�s a waste. Good accuracy where I don�t need it, poor accuracy where I do.

Now of course, since you use SMK�s with high BC�s, you don�t have this problem. Move your �standard accuracy goal� back to 500 yds and start testing blunt bullets along side the MK's. Maybe you�ll then realize how spoiled you�ve been by the SMK�s.

Quote:

---

I use boat-tailed bullets because they are easier to load...not because someone, or someone's computer, decided they have a "higher" BC than flat-based bullets.

---

Yeah, you�re right. Some nerdy Engineer�s computer just �decided� that one day and we have forever been fooled. We all know chronographs fail to operate when placed beyond 15 feet from the muzzle. When for a few hundred dollars people can buy everything they need to test it pretty accurately (as some on this board have) and the bullet companies (some of them, anyway) spend much more in testing, not to mention the Military�.you�re right. It�s just all made up. Nobody has actually tested this. Ever. It�s just a myth. No, the back end isn�t the most important end of the bullet, but it does make a contribution�or so my computer has �decided.�

Quote:

---

I'll be shooting about 2.5" lower with the Swift at 400 yards. There will also be about 6" difference in wind drift at 400 yards. If I can aim 16" high, I can hold 18.5" high.

---

Yes, you can. And with a rangefinder you know you're exactly 400 yards away.

Quote:

---

If I can hold for 11" of drift, I can hold for 17" of drift.

---

That�s where you will have problems. There is no such device to tell you exactly how much wind there is to correct for. You need to guess. Even with an �educated, practiced� guess you will be off. A little or a lot, you�ll never get it exactly right every time. So using a bullet that drifts more in the wind simply means for a given amount of error your round lands farther from the mark. Another variable to contend with, similar to using a less accurate rifle under those conditions.

Quote:

---

It takes a lot of distance for a bullet with a 20% higher BC to catch up,

---

In drop, yes. In wind drift, no. But of course at close range the difference will be small.

Quote:

---

There was a magazine article that listed actual tests of BC's and almost all of the actual numbers were lower than what's published.

---

You�re probably talking about Rick Jamison�s recent article on bonded bullets. They were not corrected to standard conditions as advertised BC�s should be. The results need to be compared relatively between the bullets. Had he done the test in Denver, they all would have tested better than advertised�except maybe, for the Barnes. Here were the results:

Bullet: BC:
Norma 180 Oryx .258
Swift 180 A-Frame .310
Speer 180 TBBC .346
Barnes 180 TSX .402
Hornady 165 InterBond .442
Nosler 180 Accubond .450
Swift 180 Scirocco .479

Quote:

---

The link to this magazine article was show on this forum about a year ago. If someone could find it again it would be of interest.

---

You�re probably talking about this one:



The same thing about the conditions and comparing them relatively applies here, too. Just like two cars drag racing on a track in Denver--they're both going to be slower than they would be at sea level. What matters is who's faster on the same day, on the same track during the same conditions.

Look at those plastic tips go! And not just because his computer said they would, Steve.

BC matters plenty to me. Or I should say coefficient of drag matters. If I have two bullets that both perform well, I'll take the one that reaches farther. It's not just about drop, but if terminal performance is everything, then realize that with expanding bullets especially, less drop = less velocity loss = better performance (within reasonable parameters.)
The manners in which different companies come up with their respective BC's are so numerous, that it's just silly to compare one with another, as though we were talking about inches or frequency or volume, where the standards are universal. What were the shooting conditions at the time of testing? What form factor did they use? Even assuming the same form factor, how much variance between the bullet shape of Brand X and the FF, as compared to that of Brand Y and FF?
But, as I said, if I have two loads that group well, at muzzle speeds I'm happy with, I'll take the one that's faster at 300 yd over the other, AEBE. Why wouldn't I?

Bwana-be, you and JonA pretty much nailed it for me. Your the first to reference Cd around here that I've read. Sure wish the bullet makers would ditch the BC approach to external ballistics.

So anyway, here I am shooting PP lead on one hand, fairly large bore at modest velocity, and on the other, a Roberts that just loves to thrash hell out of Mach 3. Why would I NOT care about BC/Cd on both? My concern reflects the reason that there aren't many that use round balls much beyond 100 yards. Wind Drift is far more significant in this discussion than trajectory, and if you doubt that, go check the cross wind deflection for the .17 HMR at 100 and 200 yards. That's precisely what a low BC will do for you. It is why the 6mm PPC dominates the .22 PPC. Drift is THE most difficult to evaluate and remedy of any of the ballistic issues we face as shooters. It is not by any means the only issue, and often means little, but it is the one thing that shooters screw up more often than the rest put together.

To those who like SD but are not too concerned with BC, there is not only a relation, they are married and in bed with each other. BC for a given form is directly proportional to SD. You like SD because of concerns regarding penetration of your quarry, well, it's gotta penetrate air too. What is good for the goose...

Idle question for all you boys and girls:

Wind deflection is a function of A) Time of Flight, B) Bullet Form, C) Drag, D) Square of the Rangewind value.

I shall step down from my soapbox now.

Jon A,
That was a good post, but since you quoted me, I'd better explain my perspective a little better.

My point was that I am not likely to take 400 yard shots to begin with. My longest shot to date was a muley buck at 375 paces back in 1970 (I think it was '70). I haven't attempted a shot near that distance since, but I haven't hunted Montana lately, either. I see deer at that distance across bean fields in northern Missouri, but I'm not nearly as tempted to shoot as I would have been 34 years ago. There are plenty of deer to be taken at more reasonable distances where I hunt.

I don't have a problem with hunters taking long shots if they are competent at long range and it is necessary, as it is in some parts of the country. I prefer to get a little closer, but I realize that is easier said than done in some places. In those cases, BC can matter, but the difference would have to be quite significant, and it still matters less than bullet accuracy, especially on long shots.

Interesting thread.