BC and Accuracy

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garandman

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Nov 17, 2009
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I would like to engage a factual, respectful educational discussion of ballistic coefficient (its definition, explanation and on-target manifestation) and accuracy (consistency of target impact, group size, trajectory at distance, etc)

Here are the ground rules:

1. All posts must stay on THIS topic.
2. No ad hominem, insult, personal attack, or profanity.Those are using force, not logic, to make your case.
3. No refernces to what has has happenned in other posts on other topics. That stuff won't be educational, here.
4. No Emoticons, off topic GIF's, memes and other unrelated material.
5. Simple statement of opinion (yours or other peoples) without explanation / logic / science / fact etc to support it will be regarded as unpersuasive.
6. Just... be nice. And factual. And patient. Be a teacher. DOn't try to win / thump your chest. Educate. DOn't insult.
7. If that is unaceeptable or undesirable, that's OK....so long as anyone of that opinion just moves on, doesn't post and does not engage here by interfering with a respectful, educational discussion.

So... here's my premise: While BC is not the only factor in accuracy, it is a significant factor in all target range distances in a bullets inherent accuracy (defined as its ability to produce small, consistent groups.

Let's start by assembline a somewhat universally accepted definition of ballistic coefficient. Here are several sources:

"Ballistic Coefficient (BC) is basically a measure of how streamlined a bullet is; that is, how well it cuts through the air. Ballistic Coefficient is essentially a measure of air drag. The higher the number the less drag, and the more efficiently the bullet cuts through the air. So for purposes of flying through the air efficiently, the bigger the BC number the better. "

Source: https://www.chuckhawks.com/bc.htm

"There are at least three ways to describe the BC. First, it is widely recognized as a figure of merit for a bullet’s ballistic efficiency. That is, if a bullet has a high BC, then it will retain its velocity better as it flies downrange from the muzzle, will resist the wind better, and will “shoot flatter.”

Source: http://www.exteriorballistics.com/ebexplained/5th/221.cfm

"The ability of the bullet to maintain velocity, in comparison to a ‘standard projectile’. A high BC bullet can maintain velocity better than a low BC bullet under the same conditions. All measures of ballistic performance including drop and wind deflection are related to the bullet’s ability to maintain velocity. In short; the higher the BC, the better the all-around ballistic performance of the bullet will be. "

Source: https://bergerbullets.com/a-better-ballistic-coefficient/

Taken as a whole, BC seems to be how efficiently a bullet handles air/ wind resistance, to minimize drag, maintain velocity, and produce a particualr trajectory.

Other reading seems to indicate BC truly manifests itself at longer ranges - maybe 3-400 yards plus. Making BC a truly (most?) significant factor for long range shooting.

So... what is BC's effect at 100 yards (sight in ranges) ?


In reality, we can mostly only guess / theorize.

But from a logical standpoint, it can be said that while BC will more prominently manifest at longer ranges, the things that a higher BC overcome (air, drag, etc) exist at EVERY range...starting 1 yard from the muzzle. Such that a bullets ability to operate efficiently doesn't magically come into existence at 300+yards. Its also exists at 100 yards.

So... at least logically (who knows what happens in the real world, with all its OTHER variables) a higher BC is desireable at all target ranges.

Numerous wildcards exist:

1. Bullet stabilization. Logically, a bullet that stabilizes at 250 feet will print better (on average) than one that stabilizes at 350 feet, and produce better groups when shooting at a 300 foot (100 yard target .) BC will not overcome an unstable bullet.

2. Inconsistencies in bullet copper jacket / internal lead core that cause instability. A bullets external form (the main driver of its BC) cannot overcome that.

3. Microscopic dents from packaging / transport.

4. Meplat deformation.

5. Microscopic barrel / rifling irregualrities.

6. Microscopic indentations from bullet loading / manufacture.

7. In short, the "external" real world is a huge variable.

(That's why this is largely a theoretical discussion. )

When evaluating group size in hundredths / thousandths of an inch, even the much lesser beneficial effects of higher BC at 100 yards (as compared to 300+ yards) are real and significant.

"Efficiency" (repeated over and over by the sources above as the main aspect of BC) leads to reduction of drag creating greaters consistency of velocity, trajectory, and therefore impact / accuracy at all distances, but most prominmently at long range.


I hold no emotional attachment to this logic / thought process.I'm open to bettter logic....most bcuz I'm trying to shoot better, with better relaoading component decisions, not win this discussion.

In the real world, I'll take a lower BC bullet that shoots well in MY gun, over a higher BC bullet every single day of the week. But not knowing that UNTIL I shoot the load, I'm going to start with higher BC bullets.... till range testing proves otherwise.

Provide facts / logic / reason / science (not just opinion, yours or some "experts" ) and I'll tip my hat and thank you very much for a new perspective.

Aaaannnnnddd.... we're off ! :) Thanx in advance for all helpful, on topic, educational, non ad hominem posts. :)
 
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Took too long to read the preamble, Ill get to my point, very few real world targets will present themselves over 700 yards,,, the reason why the USMC had to be dragged into the world of 300WM recently is based on that fact. Best BC is whatever 308 7.62 projo you favor, Myself I like the 175 SMK for an over all effective round, that can be fired from any rifle you find in the field chambered for such.

if you take center to center group size into account, its hard to beat the old M118.

0.505 bc is good enough for practical riflery

for group sizing the 155 aint bad either
 
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BC is important , but only if the shooter and his gear are consistent. A guy with a 30-30 and a 4 power scope that makes consistent hits at 300 yards is more dangerous than a guy with a $10,000.00 rig shooting Flatlines but is inconsistent as a shooter. I've seen many people spend big bucks on the latest and greatest gear and not be able shoot well beyond a 100 yards. They just can't understand why that one 3 shot group they shot at 100 doesn't = accuracy at longer distance. Those types all think that because they read 93 Confirmed Kills that they can shoot.

rant over
 
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Start your own website where you can actually make your own rules. I would be insulted if this was mine, and you thought you could play mod. Do you go to an acquaintances’ house and order him to cook you a certain dinner? Act like a guest.

You teaching someone is truly frightening. I hope you’re just saying that to scare us.

Instead of being John Fistsinyourface you should sign up for training and listen more than talk.

All your cutting and pasting seems to confuse you more than making anything clear to you. You are arguing how many angels can dance on the head of a pin @ 100 yards in regards to BC and accuracy being at all related. I thought Frank’s initial post was crystal clear. Let it go, or better yet go over to accurateshooter.com where somebody cares. You are obviously a benchrest shooter, and in the wrong place. They’re just like you over there. Enjoy!
 
Tag. Watching this.

Question.

If you have multiple bullets of identical shape, size, caliber and BC, but they are made of different materials, how does that affect real BC vs an aerodynamic BC?
Choose your projectile material.

1. 100% lead
2. Lead with copper core
3. Lead with copper jacket
4. Copper
5. Copper jacket with lead core.
6. Copper jacket with tungsten core
7. Copper jacket with aluminum core
8. Copper jacket, no core
9. Solid aluminum
10. Aluminum jacket no core
11. Titanium
12. Titanium with blueberry donut core.
 
Tag. Watching this.

Question.

If you have multiple bullets of identical shape, size, caliber and BC, but they are made of different materials, how does that affect real BC vs an aerodynamic BC?
Choose your projectile material.

1. 100% lead
2. Lead with copper core
3. Lead with copper jacket
4. Copper
5. Copper jacket with lead core.
6. Copper jacket with tungsten core
7. Copper jacket with aluminum core
8. Copper jacket, no core
9. Solid aluminum
10. Aluminum jacket no core
11. Titanium
12. Titanium with blueberry donut core.

I'll take the one with blueberry donut core and feed that to my deer this upcoming season. Maybe if they like the blueberry, they'll start showing up more to my hunting spot and that'll make it easier for me to bag a nice one lol...

On a serious note, is the only thing different material composition? I ask this because the copper jacket with tungsten core would be very "center heavy" vs the aluminum jacket no core, while both still maintaining same weight, same length, same shape & size, etc.
 
I'll take the one with blueberry donut core and feed that to my deer this upcoming season. Maybe if they like the blueberry, they'll start showing up more to my hunting spot and that'll make it easier for me to bag a nice one lol...

On a serious note, is the only thing different material composition? I ask this because the copper jacket with tungsten core would be very "center heavy" vs the aluminum jacket no core, while both still maintaining same weight, same length, same shape & size, etc.

Ahhh, Daniel-san. No say same weight, only say same size.
Whack on, whack off!
 
So... here's my premise: While BC is not the only factor in accuracy, it is a significant factor in all target range distances in a bullets inherent accuracy (defined as its ability to produce small, consistent groups.

Your premise is off. What you are describing is precision. It is only also accuracy if you are hitting your desired POI.

BC has next to nothing to do with 100yd groups. Maybe if you’re shooting in variable high winds, but not in a practical sense. Small groups are about fine tuning your components/load and getting everything just right, and that may involve using a bullet with a lower BC. Most centerfire rifle rounds are getting to 100yds before the environment has much of a chance to impose any impact (practically speaking).

This thread is nothing more than your response to the HMFIC using a Valkyrie when comparing precision in AR’s and how you said “of course the Valkyrie shoots better, it’s using a higher BC bullet”.

Learn some humility. You know about 15% of what you think you do, but try and challenge some very knowledgeable ppl, and then get butthurt when ppl don’t agree with your inaccurate logic. If you’d be open to learning, you’ll find this is a very good site, with a wealth of information.
 
Your premise is off. What you are describing is precision. It is only also accuracy if you are hitting your desired POI.

BC has next to nothing to do with 100yd groups. Maybe if you’re shooting in variable high winds, but not in a practical sense. Small groups are about fine tuning your components/load and getting everything just right, and that may involve using a bullet with a lower BC. Most centerfire rifle rounds are getting to 100yds before the environment has much of a chance to impose any impact (practically speaking).

This thread is nothing more than your response to the HMFIC using a Valkyrie when comparing precision in AR’s and how you said “of course the Valkyrie shoots better, it’s using a higher BC bullet”.

Learn some humility. You know about 15% of what you think you do, but try and challenge some very knowledgeable ppl, and then get butthurt when ppl don’t agree with your inaccurate logic. If you’d be open to learning, you’ll find this is a very good site, with a wealth of information.

He'd rather write a novel than do some actual research.
 
Hi,

Ok, I am going to quote myself from a post last night in regards to a member complaining about how he thought he was being treated because I do not feel like typing it all over again.
Ironically Paparock Jr is involved in that thread too...
If everyone would follow these basic and very simple "suggestions" they would benefit greatly from this forum..IF not..O well :)

Sincerely,
Theis

Hi,

Ok since I am still at office waiting on conference call with my Russian friends I will attempt to put together a brief post on how to get the most from Snipers Hide..Theis style :)

1. Take some time to read other post of the members that reply to your post or reply to a post you read. This forum is a very unique place on the www and you can find out a lot about particular member(s) by reading their post/replies.
We have guys here that were part of and/or currently part of some of the baddest .mil and .gov entities in the world here.
We have guys that own, run, and work at some of the largest firearms/defense industry companies in the world.
We have guys here that consult to ballistic R&D firms, PMC firms, foreign governments, etc etc.

2. If you post something that is your opinion you better state it as your opinion or be ready and able to back it up as fact.

3. Whatever it is you think you know, someone on here knows it better and/or in more detail than you.
Know what you do not know and you will get lots of assistance from this forum.

4. The guys that will tell you to F' off are "triggered" by someone posting information they read, watched or heard but attempt to post it as if they have direct knowledge of the information.
This forum runs on the premise of Better to be knowledgeable by application than knowledgeable by association so do not attempt to act like you know something just because you heard it on youtube....you will get eaten alive if you do.

5. Read and learn the mistakes of this thread...

Sincerely,
Theis
 
FYI.... I take all the ad hominem and other foolishness as an admission of having no intelligent response. Some of you clearly never matured beyond high school. Jr. high, in fact. Thumping your chest. Being crass instead of factual or engaging with adult discussion. Trying to tell me what to do, how to act, RATHER THAN engaging the conversation. You seem threatened by a simple logical layout of the facts.

Carry on. Very entertaining. :)
 
Tag. Watching this.

Question.

If you have multiple bullets of identical shape, size, caliber and BC, but they are made of different materials, how does that affect real BC vs an aerodynamic BC?
Choose your projectile material.

1. 100% lead
2. Lead with copper core
3. Lead with copper jacket
4. Copper
5. Copper jacket with lead core.
6. Copper jacket with tungsten core
7. Copper jacket with aluminum core
8. Copper jacket, no core
9. Solid aluminum
10. Aluminum jacket no core
11. Titanium
12. Titanium with blueberry donut core.

You forgot the depleted uranium.
 
1. All posts must stay on THIS topic.
2. No ad hominem, insult, personal attack, or profanity.Those are using force, not logic, to make your case.
3. No refernces (sp) to what has has happenned (sp) in other posts on other topics. That stuff won't be educational, here.
4. No Emoticons, off topic GIF's, memes and other unrelated material.
I’d pay attention to what @THEIS posted. Good advice.

Re: #1- this is Snipers Hide, nothing stays on topic
Re: #2- that takes all the fun out
Re: #3- read @THEIS post again. You have that depth of expertise at hand and won’t reference it? Wow.
Re: #4- no pics evidently so it didn’t happen

Watching now as this is potentially fun. “Blueberry Donut Core?” Classic.
 
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Hi,

Ok, I am going to quote myself from a post last night in regards to a member complaining about how he thought he was being treated because I do not feel like typing it all over again.
Ironically Paparock Jr is involved in that thread too...
If everyone would follow these basic and very simple "suggestions" they would benefit greatly from this forum..IF not..O well :)

Sincerely,
Theis
A thread that will go down in infamy. I can’t believe it’s been a year.
 
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I would like to know who edited my OP, noting spelling errors. Seems very dishonest.

I been wondering why ppl been beating me up here for things I never said. I had thot it was just musunderstanding.

NOW I'm wondering if someone with the abilty to do so CHANGED my posts to put words in my mouth and totally fabricate what I 've said.

SMH.
 
I would like to know who edited my OP, noting spelling errors. Seems very dishonest.

I been wondering why ppl been beating me up here for things I never said. I had thot (sp) it was just musunderstanding (sp).

NOW I'm wondering if someone with the abilty (sp) to do so CHANGED my posts to put words in my mouth and totally fabricate what I 've (sp) said.

SMH.

Hi,

Now we getting somewhere...
Did you not make those mistakes? Sorta like ones highlighted in the quote above?

Sincerely,
Theis
 
He was spot on with most of us have not matured since high school. Why just the other day Mrs. Culpeper said the same thing with, "You're almost 15 years old." I don't care if it is a five star restaurant. If they have fried catfish and fries on the menu than I'm going to get excited and drown it with a half a bottle if catsup.
 
I would like to know who edited my OP, noting spelling errors. Seems very dishonest.

I been wondering why ppl been beating me up here for things I never said. I had thot it was just musunderstanding.

NOW I'm wondering if someone with the abilty to do so CHANGED my posts to put words in my mouth and totally fabricate what I 've said.

SMH.

Now you sound like Yossarian. You're not getting out of flying more missions by acting like you're crazy.
 
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FYI.... I take all the ad hominem and other foolishness as an admission of having no intelligent response. Some of you clearly never matured beyond high school. Jr. high, in fact. Thumping your chest. Being crass instead of factual or engaging with adult discussion. Trying to tell me what to do, how to act, RATHER THAN engaging the conversation. You seem threatened by a simple logical layout of the facts.

Carry on. Very entertaining. :)
Wow. Reminds me of Russia collusion; accuse your enemies of that which you are guilty of doing.

Who came in with pics of groups @ 100 telling us how great they can shoot? Chest thump much? We don’t do that shit. It’s not necessary, because there are scoreboards.
Even for paper punchers.

Talking about how great you are is not the same thing as winning a match against real marksmen. The guys who do well don’t have to chest thump and talk about it. We watch the scores and know who the are. They’re reading this thread. The score speaks for itself. The people who chest thump invariably aren’t even on the board. They only think they can shoot.

Go win a match, and then come back with a link to your score and I’ll STFU.
 
Hi,

Just a few questions...

1. WTF did I just attempt to read?
2. Back on topic....Who in the hell uses jacketed bullets? Might as well be using paper patched trash.
3. Off topic...How is Paparock Jr still here? Did someone run over the ban cat?

Sincerely,
Theis

Mr, the kitty has fallen over due to exhaustion. You're privy to that secret post,so catch up with the rest of us. :)
 
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I would like to know who edited my OP, noting spelling errors. Seems very dishonest.

I been wondering why ppl been beating me up here for things I never said. I had thot it was just musunderstanding.

NOW I'm wondering if someone with the abilty to do so CHANGED my posts to put words in my mouth and totally fabricate what I 've said.

SMH.

" I hold no emotional attachment to this logic / thought process. "

Are you sure?
 
OP, I recommend you just STFU and read all of these:


 
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No, I do not. None of you clowns have really responded to my actual post.

What I find truly disturbing is SOMEONE in this forum with the power to do so literally making changes to ***MY***posts.
There have been many answers, you just don't like them. This forum really is a goldmine of information. If you spent as much time researching as you do writing novels, you would know that.
 
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There have been many answers, you just don't like them. This forum really is a goldmine of information. If you spent as much time researching as you do writing novels, you would know that.


So you would be OK with someone chaning YOUR posts for you? Literally putting words in your mouth you didn't say..... you don't have the moral courage / fibre to oppose that? You want to ingratiate yourself to that kind of person THAT much? To be part of that kind of inner circle?

Really?
 
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