HuntingNut
HuntingNut
   Login or Register
HomeCommunity ForumsPhoto AlbumsRegister
     
 

User Info

Welcome Anonymous


Membership:
Latest: RichardZ
New Today: 0
New Yesterday: 0
Overall: 13126

People Online:
Members: 0
Visitors: 558
BOT: 1
Total: 559
Who Is Where:
 Visitors:
01: Forums
02: Forums
03: Forums
04: Forums
05: Forums
06: Forums
07: Home
08: Your Account
09: Forums
10: Forums
11: Forums
12: Forums
13: Forums
14: Forums
15: Forums
16: Forums
17: Forums
18: Forums
19: Forums
20: Forums
21: Home
22: Forums
23: Forums
24: Your Account
25: Forums
26: Forums
27: Forums
28: Forums
29: Forums
30: Forums
31: Photo Albums
32: Forums
33: Forums
34: Forums
35: Your Account
36: Forums
37: Forums
38: Your Account
39: Forums
40: Forums
41: Forums
42: Forums
43: Forums
44: Forums
45: Forums
46: Forums
47: Forums
48: Forums
49: Forums
50: Your Account
51: Forums
52: Home
53: Forums
54: Your Account
55: Forums
56: Forums
57: Forums
58: Forums
59: Forums
60: Forums
61: Photo Albums
62: Home
63: Your Account
64: Home
65: Forums
66: Forums
67: Forums
68: Forums
69: Your Account
70: Forums
71: Forums
72: Forums
73: Forums
74: Photo Albums
75: Photo Albums
76: Forums
77: Forums
78: Your Account
79: Photo Albums
80: Forums
81: Photo Albums
82: Forums
83: Forums
84: Forums
85: Forums
86: Forums
87: Forums
88: Forums
89: Forums
90: Forums
91: Home
92: Forums
93: Forums
94: Forums
95: Photo Albums
96: Forums
97: Forums
98: Forums
99: Forums
100: Photo Albums
101: Photo Albums
102: Forums
103: Forums
104: Photo Albums
105: Forums
106: Forums
107: Your Account
108: News
109: Forums
110: Photo Albums
111: Forums
112: Your Account
113: Home
114: Forums
115: Forums
116: Forums
117: Forums
118: Forums
119: Forums
120: Forums
121: Your Account
122: Forums
123: Forums
124: Forums
125: Forums
126: Forums
127: Home
128: Forums
129: Forums
130: Forums
131: Forums
132: Your Account
133: Forums
134: Forums
135: Your Account
136: Photo Albums
137: Forums
138: Forums
139: Forums
140: Forums
141: Photo Albums
142: Your Account
143: Forums
144: Your Account
145: Your Account
146: Forums
147: Forums
148: Forums
149: Your Account
150: Your Account
151: Forums
152: Home
153: Forums
154: Forums
155: Photo Albums
156: Forums
157: Forums
158: Forums
159: Forums
160: Photo Albums
161: Forums
162: Forums
163: Forums
164: Forums
165: Forums
166: Forums
167: Forums
168: Your Account
169: Forums
170: Forums
171: Your Account
172: Forums
173: Photo Albums
174: Forums
175: Forums
176: Forums
177: Forums
178: Forums
179: Forums
180: Forums
181: Forums
182: Your Account
183: Forums
184: Forums
185: Your Account
186: Forums
187: Forums
188: Forums
189: Forums
190: Home
191: Forums
192: Forums
193: Forums
194: Your Account
195: Forums
196: Forums
197: Your Account
198: Forums
199: Photo Albums
200: Your Account
201: Home
202: Forums
203: Forums
204: Home
205: Your Account
206: Your Account
207: Forums
208: Photo Albums
209: Forums
210: Forums
211: Your Account
212: News
213: Home
214: Forums
215: Photo Albums
216: Forums
217: Forums
218: Forums
219: Forums
220: Your Account
221: Forums
222: Forums
223: Forums
224: Your Account
225: Forums
226: Home
227: Photo Albums
228: Home
229: Forums
230: Your Account
231: Photo Albums
232: Forums
233: Forums
234: Forums
235: Photo Albums
236: Your Account
237: Home
238: Forums
239: Forums
240: Forums
241: Forums
242: Forums
243: Forums
244: Photo Albums
245: Forums
246: Forums
247: Forums
248: Forums
249: Forums
250: Forums
251: Forums
252: Forums
253: Forums
254: Forums
255: Forums
256: Forums
257: Forums
258: Forums
259: Your Account
260: Forums
261: Photo Albums
262: Photo Albums
263: Forums
264: Forums
265: Forums
266: Forums
267: Forums
268: Forums
269: Forums
270: Forums
271: Forums
272: Photo Albums
273: Forums
274: Forums
275: Forums
276: Photo Albums
277: Photo Albums
278: Your Account
279: Forums
280: Forums
281: Photo Albums
282: Forums
283: Forums
284: Your Account
285: Your Account
286: Home
287: Forums
288: Forums
289: Forums
290: Forums
291: Forums
292: Forums
293: Your Account
294: Forums
295: Forums
296: Forums
297: Photo Albums
298: Forums
299: Home
300: Photo Albums
301: Your Account
302: Home
303: Forums
304: Forums
305: Forums
306: Forums
307: Your Account
308: Forums
309: Forums
310: Forums
311: Forums
312: Forums
313: Forums
314: Forums
315: Forums
316: Your Account
317: Forums
318: Forums
319: Forums
320: Forums
321: Your Account
322: Forums
323: Forums
324: Forums
325: Forums
326: Forums
327: Forums
328: Forums
329: Photo Albums
330: Forums
331: Forums
332: Photo Albums
333: Forums
334: Forums
335: Forums
336: Forums
337: Your Account
338: Forums
339: Home
340: Forums
341: Forums
342: Your Account
343: Forums
344: Forums
345: Forums
346: Forums
347: News
348: Forums
349: Forums
350: Forums
351: Forums
352: Forums
353: Home
354: Forums
355: Forums
356: Your Account
357: Forums
358: Photo Albums
359: Forums
360: Forums
361: Forums
362: Forums
363: Forums
364: Forums
365: Forums
366: Photo Albums
367: Home
368: Forums
369: Home
370: Forums
371: Forums
372: Forums
373: Home
374: Home
375: Forums
376: Your Account
377: Forums
378: Forums
379: Forums
380: Forums
381: Your Account
382: Forums
383: Forums
384: Forums
385: Forums
386: Forums
387: Forums
388: Photo Albums
389: Forums
390: Forums
391: Forums
392: Your Account
393: Forums
394: Forums
395: Your Account
396: Home
397: Your Account
398: Photo Albums
399: Forums
400: Forums
401: Photo Albums
402: Photo Albums
403: Forums
404: Forums
405: Forums
406: Forums
407: Forums
408: Your Account
409: Forums
410: Home
411: Forums
412: Forums
413: Forums
414: Photo Albums
415: Forums
416: Forums
417: Forums
418: Forums
419: Photo Albums
420: Forums
421: Forums
422: Forums
423: Forums
424: Forums
425: Forums
426: Forums
427: Your Account
428: Forums
429: Forums
430: Your Account
431: Forums
432: Your Account
433: Forums
434: Forums
435: Photo Albums
436: Forums
437: Your Account
438: Photo Albums
439: Forums
440: Forums
441: Photo Albums
442: Forums
443: Forums
444: Forums
445: Forums
446: Your Account
447: Home
448: Photo Albums
449: Forums
450: Forums
451: Forums
452: Forums
453: Forums
454: Forums
455: Photo Albums
456: Forums
457: Forums
458: Your Account
459: Forums
460: Your Account
461: Your Account
462: Forums
463: Forums
464: Forums
465: Home
466: Forums
467: Forums
468: Forums
469: Forums
470: Your Account
471: Forums
472: Forums
473: Forums
474: Forums
475: Forums
476: Photo Albums
477: Forums
478: Your Account
479: Home
480: Forums
481: Home
482: Forums
483: Your Account
484: Forums
485: Forums
486: Home
487: Forums
488: Home
489: Forums
490: Your Account
491: Forums
492: Home
493: Forums
494: Forums
495: Photo Albums
496: Forums
497: Photo Albums
498: Photo Albums
499: Forums
500: Forums
501: Forums
502: Forums
503: Forums
504: Forums
505: Forums
506: Forums
507: Your Account
508: Home
509: Forums
510: Forums
511: Forums
512: Forums
513: Photo Albums
514: Forums
515: Forums
516: Your Account
517: Forums
518: Forums
519: Forums
520: Forums
521: Forums
522: Your Account
523: Forums
524: Forums
525: Forums
526: Forums
527: Forums
528: Forums
529: Forums
530: Forums
531: Forums
532: Home
533: Forums
534: Home
535: Forums
536: Your Account
537: Photo Albums
538: Your Account
539: Forums
540: Forums
541: Forums
542: Forums
543: Forums
544: Statistics
545: Your Account
546: Forums
547: Forums
548: Forums
549: Forums
550: Forums
551: Your Account
552: Forums
553: Forums
554: Forums
555: Forums
556: Your Account
557: Forums
558: Forums
  BOT:
01: State F&G Agencies

Staff Online:

No staff members are online!
 

Coppermine Stats
Photo Albums
 Albums: 308
 Pictures: 2451
  · Views: 820725
  · Votes: 1316
  · Comments: 86
 

Ballistic Coefficient
Discussion that doesnt fit other Topics
Post new topic   Reply to topic   Printer Friendly Page    Forum Index » General

View previous topic :: View next topic  
Author Message
Knifeboy
Member
Member


Joined: Feb 09, 2005
Posts: 165
Location: The Arizona desert

PostPosted: Fri Apr 08, 2005 4:33 pm    Post subject: Ballistic Coefficient Reply with quote

I dont want to sound dumb, but I just want to know what the ballistic coefficient is? I thought this would be the bunch to ask, you guys know a lot about ballistics. Any info on this topic will be appreciated.

Thanks,
Knifeboy

_________________
I'd rather be lucky than good.
Back to top
View user's profile Photo Gallery
Blaine
Member
Member


Joined: Feb 24, 2005
Posts: 260
Location: Maine

PostPosted: Fri Apr 08, 2005 5:49 pm    Post subject: Re: Ballistic Coefficient Reply with quote

The ballistic coefficient is a comparison number to a standard established by the military for a artillery round. This figure is set at 1.000 and all other projectiles are compared to it. Generally speaking, the Ballistic Coefficient (BC) is a figure used for comparison purposes that takes into account a bullet's shape vs sectional density & weight. The higher the number.....the better a bullet will "slip" through the air and maintain its velocity. Various factors contribute to a bullet's BC. For example the shape of the nose (the more pointed/streamlined the higher the BC) and the tail (a boat tail design produces a higher BC). All these factors added together are used to establish the bullet's BC. Don't ask about the formula used....you wouldn't want to know. Confused What it all adds up to is that the higher a bullet's BC, the more velocity it maintains down range. Hope this helps.

Blaine

_________________
Shoot straight and above all shoot SMART....and remember God is still in control !!!!
Back to top
View user's profile Photo Gallery
DallanC
Site Admin
Site Admin


Joined: Jan 18, 2005
Posts: 3571
Location: Utah

PostPosted: Fri Apr 08, 2005 8:31 pm    Post subject: Re: Ballistic Coefficient Reply with quote

Very good description... I would only add that 1.0 BC is the perfect theoretical bullet... which doesnt exist in the real world. It is a value to describe how well the bullet travels through the air. You get near or above .5 BC and you have a pretty amazing bullet on your hands.


-DallanC
Back to top
View user's profile Photo Gallery
slamfire
Rookie Member
Rookie Member


Joined: Feb 07, 2005
Posts: 19

PostPosted: Sun May 15, 2005 9:18 pm    Post subject: Re: Ballistic Coefficient Reply with quote

Some folks do not agree with the calculations.

Ballistic balderdash!

Twisted Evil
Back to top
View user's profile Photo Gallery
Flint54
Member
Member


Joined: Apr 09, 2005
Posts: 389
Location: North Carolina

PostPosted: Sun May 15, 2005 11:03 pm    Post subject: Re: Ballistic Coefficient Reply with quote

Wink BUT< the actual B.C. from your firearm may (Almost Always) not be that published by the Manufacturer. Depending on the condition of your bore, the # of lands & grooves, the depth of the rifling, the stability & condition of the bullet upon its exit, the condition of the crown and the Rolling Eyes phase of the moon, tides and who knows what else!

One very imoprtant thing to remember is the condition of the point of your bullet and the base! Those bullets that have been altered by a seater die will positively have a lower BC. If the base is damaged in any way it will also alter the BC. What I'm basicly saying is that to get the true BC you have to chronograph your ammunition at two distances, the muzzle and (I use 100 yds) and then feed the data into my PACT Chrono and it will give me a corrected BC. Most of my tests have shown a diffrence of @ .010 - .020 from published data.

Does it matter, IMO for hunting I doubt it, but for long range work most decidedly!

Just another variable in our quest for perfection! Rolling Eyes Wink
Back to top
View user's profile Photo Gallery
DallanC
Site Admin
Site Admin


Joined: Jan 18, 2005
Posts: 3571
Location: Utah

PostPosted: Mon May 16, 2005 10:53 am    Post subject: Re: Ballistic Coefficient Reply with quote

The Ballistic Coefficent is a value that quantifys how a bullet travels through the air enroute to target. Of course it exists. That it is dynamic instead of being static is a different issue.


-DallanC
Back to top
View user's profile Photo Gallery
Blaine
Member
Member


Joined: Feb 24, 2005
Posts: 260
Location: Maine

PostPosted: Wed May 18, 2005 3:02 pm    Post subject: Re: Ballistic Coefficient Reply with quote

Comparing BC's is like comparing the mileage estimates on new car stickers...it is for comparison. The number doesn't mean anything in real terms, but by comparing the BC's of bullets, you get an idea how the velocity will hold up down range. I agree that for hunting situations (in my area less than 200 yards), the bullet construction has more to do with stopping a deer than an extra 50 fps or so. But if you can have a bullet that is well constructed and still has a high BC, why not use it? Often times a more stream lined bullet (higher BC) will stabilize better and therefore be more accurate. That's not a given, but it sometimes works out that way.

Blaine

_________________
Shoot straight and above all shoot SMART....and remember God is still in control !!!!
Back to top
View user's profile Photo Gallery
GroovyJack
Member
Member


Joined: May 21, 2005
Posts: 621
Location: Bama

PostPosted: Sun May 22, 2005 6:56 pm    Post subject: Re: Ballistic Coefficient Reply with quote

Also different velocities produce different BC's ..
Lets say we have a theoretical bullet with a BC of .500 in 7mm caliber .
You launch this bullet out of yur 7 mag at 3000 fps you have one BC
You launch out of yur 7/08 several hundred fps less and you have another BC ..
As the bullet slows down the BC changes .. Also while it is true that a boattail has a better BC it does not mean the boattail is 'more accurate'
Jack

_________________
My Goal In Life Is To Be As Good Of A Person As My Dog Already Thinks I Am
Back to top
View user's profile
1895ss
Super Member
Super Member


Joined: Jul 21, 2005
Posts: 2612
Location: Not Here...!!

PostPosted: Thu Aug 11, 2005 10:12 pm    Post subject: Re: Ballistic Coefficient Reply with quote

Ballistic Coefficient (BC) is basically a measure of how streamlined a bullet is; that is, how well it cuts through the air. Mathematically, it is the ratio of a bullet's sectional density to its coefficient of form. 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.

BC is what determines trajectory and wind drift, other factors (velocity among them) being equal. BC changes with the shape of the bullet and the speed at which the bullet is traveling, while sectional density does not. Spitzer, which means pointed, is a more efficient shape than a round nose or a flat point. At the other end of the bullet, a boat tail (or tapered heel) reduces drag compared to a flat base. Both increase the BC of a bullet.

For example, a Hornady 100 grain round nose 6mm bullet has a BC of .216; a Hornady 100 grain spire point 6mm bullet has a BC of .357, and a Hornady 100 grain boat tail spire point 6mm bullet has a BC of .400. All three of these bullets have a sectional density (which is the ratio of a bullet's diameter to its weight) of .242, because they are all .243" in diameter and weigh 100 grains. But the more streamlined bullets have a higher ballistic coefficient. They are the ones to choose for long range shooting where a flatter trajectory is important.

To illustrate the practical difference between these three styles of bullets, let's use Hornady's trajectory figures for the 100 grain 6mm bullets above. Starting all three bullets at a muzzle velocity of 3100 fps from a scoped 6mm rifle zeroed at 300 yards, the trajectories are as follows.

.243" 100 grain Round Nose (BC .216): -1.5" @ muzzle, +4.8" @ 100 yards, +6" @ 200 yards, 0 at 300 yards, -15.9" @ 400 yards, -46" @ 500 yards.

.243" 100 grain Spire Point (BC .357): -1.5" @ muzzle, +3.8" @ 100 yards, +4.7" @ 200 yards, 0 @ 300 yards, -11.1" @ 400 yards, -30.5" @ 500 yards.

.243" 100 grain Spire Point BT (BC .400): -1.5" @ muzzle, +3.6" @ 100 yards, +4.4" @ 200 yards, 0 @ 300 yards, -10.4" @ 400 yards, -28.6" @ 500 yards.

There is a pretty big difference in trajectory between the round nose bullet and the two pointed bullets, making it obvious why it is folly to choose a round nose bullet for long range shooting with a high velocity rifle like a 6mm Remington or .243 Winchester. Also notice the big difference in BC between the round nose bullet (.216) and the spire point bullet (.357).

But there is less difference between the trajectory of the flat base spire point bullet and the boat tail spire point bullet. The boat tail helps, but not nearly as much as the point on the front of the bullet. The boat tail bullet had .3" inch less rise at 200 yards, and 1.9" less fall out at 500 yards. These differences are real, but unlikely to make or break a shot at a big game animal. This is shown by the smaller difference in BC between the two pointed bullets, .357 for the flat base and .400 for the boat tail.

To further assess the importance of a boat tail, note these pairs of Speer spitzer bullets of the same weight and caliber. In each pair, the first bullet has a flat base, and the second has a boat tail.

.243" (6mm) 100 grain, BC .351
.243" (6mm) 100 Grain BT, BC .430

.257" (.25) 100 grain, BC .369
.257" (.25) 100 grain BT, BC .393

.277" (.270) 130 grain, BC .408
.277" (.270) 130 grain BT, BC .449

.308" (.30) 165 grain, BC .433
.308" (.30) 165 grain BT, BC .477

A list of pointed (spitzer type) hunting bullets considered a good bet for long range shooting in their respective calibers, with their ballistic coefficients, follows. Boat tail bullets are designated "BT," all other bullets have flat bases.

All of the figures that follow are taken from the Speer Reloading Manual Number 13. The same weight bullets from other manufacturers will have different BC's, because they are slightly different shapes. But these Speer numbers are as typical as any, and being from the same source they are useful for purposes of comparison.

.224" (.22) 55 grain, BC .255
.243" (6mm) 90 grain, BC .385
.243" (6mm) 100 grain BT, BC .430
.257" (.25) 100 grain BT, BC .393
.257" (.25) 120 grain BT, BC .435
.264" (6.5mm) 120 grain, BC .433
.264" (6.5mm) 140 grain, BC .496
.277" (.270) 130 grain BT, BC .449
.284" (7mm) 145 grain, BC .457
.308" (.30) 150 grain BT, BC .423
.308" (.30) 165 grain BT, BC .477
.311" (.303) 150 grain, BC .411
.323" (8mm) 150 grain, BC .369
.338" (.338) 200 grain, BC .448
.375" (.375) 270 grain BT, BC .429

Note that with bullets of the same weight and style, such as the 100 grain .243" and .257" bullets or the 150 grain .311" and .323" bullets, the smaller diameter bullet always has the superior BC due to its better sectional density.

As examples of very streamlined bullets, note the BC of these Speer match type bullets. These are all pointed hollow point, boat tail bullets.

.224" (.22) 52 grain Match, BC .253
.284" (7mm) 145 grain Match, BC .465
.308 (.30) 168 grain Match, BC .480
.308 (.30) 190 grain Match, BC .540

Note that in the .308 pair, the heavier bullet (which has the greatest sectional density) has the better BC. The extremely poor SD of the .224" bullet lowers its BC, even though its shape is similar to the others.

Which explains why .22 bullets drop so much at long range and are so subject to wind drift, compared to larger caliber bullets with superior sectional densities (and hence, BC's). At a MV of 3100 fps a .224" Speer 52 grain BTHP Match bullet zeroed for 300 yards has a 500 yard drop of -43.9 inches, not much better than the 6mm round nose bullet in our trajectory examples near the beginning of this article. An interesting subject, this ballistic coefficient, and worth paying attention to when you select a bullet (or a caliber) for long range shooting.

I hope this helps Smile
Back to top
View user's profile Send e-mail
1895ss
Super Member
Super Member


Joined: Jul 21, 2005
Posts: 2612
Location: Not Here...!!

PostPosted: Fri Aug 12, 2005 7:45 pm    Post subject: Re: Ballistic Coefficient Reply with quote

By the way, I didn't write the article I posted. I got that from somewhere years ago and I thought it was a pretty good example, that's why I kept it and posted it here.

_________________
A cruel truth is much more desirable than a really nice lie.
'Tis far better to walk alone than to follow a crowd or an a**hole going the wrong way.
Back to top
View user's profile Send e-mail
delboy
Member
Member


Joined: Apr 21, 2005
Posts: 240
Location: London England

PostPosted: Tue Aug 16, 2005 6:15 pm    Post subject: Re: Ballistic Coefficient Reply with quote

Hey Flinty, what's the BC of the stones and nuts & bolts that you shoot?
Seriously though, does anyone have any clues as to where I can find the BC figures on airgun pellets? I contacted H&N in Germany but they didn't grace me with a reply. I have a ballistic table for air rifles but without the BC figures it ain't worth Jack......... I can't seem to find anything covering pellets on the net, so any leads would be gratefully received. Thanks guys,
Del

_________________
There are few problems in life that cannot be solved with sufficient high explosive........
Back to top
View user's profile
Blaine
Member
Member


Joined: Feb 24, 2005
Posts: 260
Location: Maine

PostPosted: Wed Aug 17, 2005 6:29 pm    Post subject: Re: Ballistic Coefficient Reply with quote

Based on the shape and weight of air rifle pellets, I would say the BC would be so low as to be un-useful. The shape of most pellets I've seen are not very "sleek" compared to rifle bullets.

_________________
Shoot straight and above all shoot SMART....and remember God is still in control !!!!
Back to top
View user's profile Photo Gallery
delboy
Member
Member


Joined: Apr 21, 2005
Posts: 240
Location: London England

PostPosted: Thu Aug 18, 2005 4:48 pm    Post subject: Re: Ballistic Coefficient Reply with quote

Maybe not Blaine, but they take some beating for sheer accuracy - will any of your rifles CONSISTENTLY make one cloverleaf shaped hole in a target at 50yds. ? Can you light a match at 20yds. without breaking the wood? Hmmm........ (Not that there is much point in doing either - just fun shooting) I can also take a crow or a woodpigeon with a headshot at 60yds. which I don't think is bad for a "puffer".

_________________
There are few problems in life that cannot be solved with sufficient high explosive........
Back to top
View user's profile
Display posts from previous:   
Post new topic   Reply to topic   Printer Friendly Page    Forum Index » General
Page 1 of 1
All times are GMT - 7 Hours



Jump to:  


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum


Valid CSS! Valid HTML 4.01!
Click to check if this page is realy HTML 4.01 compliant for speed :)

All logos and trademarks in this site are property of HuntingNut.com.
The comments are property of their posters, all the rest © 2011 by HuntingNut.com
Interactive software released under GNU GPL, Code Credits, Privacy Policy

.: Upgraded to DragonFly 9.2 by *Dizfunkshunal* :.