The ballistic coefficient
08-07-2009, 01:22 PM
#1
Giant Nontypical
Thread Starter
Join Date: Nov 2005
Posts: 6,585
The ballistic coefficient
I have seen and heard comments from time to time like
"it really doesn't make much difference"
so less just take a look at the difference.
With a SW250 gr bullet at the velocity recommended for the Omega Nikon scope as a starting point.
Shock Wave with a calculated BC of .199 to .2 at my sea level and conditions and a XTP with a calculated BC of .150.
we will look for some answers.
SW 250 gr "0" at 100yds has 10 inches drop at 200 yds and 18 inches at 250 with 999 Foot pounds of energy left.
The XTP 250 gr "0" at 100yds has a drop of 12 inches at 200yds and 26 at 250 yds with 725 foot pounds of energy left.
To me the drop in energy is more important than the drop in elevation. There are several publications out that recommend a minimum of 800 foot pounds of energy for deer. to me that makes the blunt bullets marginal at 200 yds and that's with 120 gr of BH209 not to say anything of some of the weaker powders.
Most of us don't take 200+yd shots any way but there are a few that do and I have taken both deer and bear at 180 yds so I am kind of interested in the subject.
What do you think?
Assuming good enough accuracy?
I can hit the 250 yd 6 inch gong any time the wind is reasonable is that good enough? Lee
"it really doesn't make much difference"
so less just take a look at the difference.
With a SW250 gr bullet at the velocity recommended for the Omega Nikon scope as a starting point.
Shock Wave with a calculated BC of .199 to .2 at my sea level and conditions and a XTP with a calculated BC of .150.
we will look for some answers.
SW 250 gr "0" at 100yds has 10 inches drop at 200 yds and 18 inches at 250 with 999 Foot pounds of energy left.
The XTP 250 gr "0" at 100yds has a drop of 12 inches at 200yds and 26 at 250 yds with 725 foot pounds of energy left.
To me the drop in energy is more important than the drop in elevation. There are several publications out that recommend a minimum of 800 foot pounds of energy for deer. to me that makes the blunt bullets marginal at 200 yds and that's with 120 gr of BH209 not to say anything of some of the weaker powders.
Most of us don't take 200+yd shots any way but there are a few that do and I have taken both deer and bear at 180 yds so I am kind of interested in the subject.
What do you think?
Assuming good enough accuracy?
I can hit the 250 yd 6 inch gong any time the wind is reasonable is that good enough? Lee
08-07-2009, 02:39 PM
#3
Nontypical Buck
Join Date: Jan 2008
Location:
Posts: 1,408
The other factor is that bullets with lower BC will have greater wind drift. This is even more important than drop, as drop is easy to calculate and compensate for today with laser rangefinders. I would be interested for you to run the numbers given a 10mph with your example to see what the difference in drift is. Wind is rarely an issue under 150 yds, but over that it becomes much more significant. When switching to higher BC bullets of higher weight the difference in wind drift is substantial. I don't have data on hand for two bullets of the same weight like in your example to run.
In your example, there was 8 inches difference in drop. While I agree with you that the energy is more important, 8 inches is a significant amount to me. Now stretch those numbers out to 300 yards...
In your example, there was 8 inches difference in drop. While I agree with you that the energy is more important, 8 inches is a significant amount to me. Now stretch those numbers out to 300 yards...
08-07-2009, 06:22 PM
#4
Nontypical Buck
Join Date: Mar 2009
Location: Saxonburg Pa
Posts: 3,925
Let's really think about this for a minute. If guy's on TV can shoot Pronghorn with a compound bow, we surely can practice are hunting skills enough to get close to shoot a Deer with a pistol bullet from a Muzzleloader. The guy's who say it doesnt matter are the guy's scouting area's to hunt to keep the shot around 50 to 100yds.
Of course the BC matters when you are shooting over two hundred yards for sure. I agree 100%. There are only a select few that hafto or want to shoot there animals over 200yards with a ML. As Spaniel mentioned, you will be really shocked what a 10mph wind will do to a XTP at 225yards.
Of course the BC matters when you are shooting over two hundred yards for sure. I agree 100%. There are only a select few that hafto or want to shoot there animals over 200yards with a ML. As Spaniel mentioned, you will be really shocked what a 10mph wind will do to a XTP at 225yards.
08-07-2009, 06:56 PM
#5
Giant Nontypical
Thread Starter
Join Date: Nov 2005
Posts: 6,585
Wind drift depending on sea level this will vary some, I figured it for my 600 ft above sea level.
Bullet---yds----drift----Bullet---yds----drift
XTP250-150----9"------SW250-150-----6.5"
--------200----16.9------------200----12
--------250----27--------------250----19
--------300----39.6------------300----29
I figured 10 miles per hour with the answer in inches.
I realize that different parts of the country and other countries may vary greatly but except during bad weather we rarely see any wind over about 6 miles per hour here.
Lee
Bullet---yds----drift----Bullet---yds----drift
XTP250-150----9"------SW250-150-----6.5"
--------200----16.9------------200----12
--------250----27--------------250----19
--------300----39.6------------300----29
I figured 10 miles per hour with the answer in inches.
I realize that different parts of the country and other countries may vary greatly but except during bad weather we rarely see any wind over about 6 miles per hour here.
Lee
08-07-2009, 07:50 PM
#6
Boone & Crockett
Join Date: Aug 2004
Location: Idaho
Posts: 11,703
Lee
For myself only I am 200 yard shooter max - that is my self imposed limit. Next the chances of getting a decent 200 yard shot are really remote in Idaho - well where I hunt. I would bet my average shot over 40 years of hunting is 60 yards max.
I have absolutely no need to shoot a point type bullet from a ML unless it were a Nosler, Barnes, or and hopefully the Lehigh.
I need a bullet that will perform equally well from 20 yards to 200 yards at what ever velocity it has at the time of impact. The SST/SW and most other pointy bullets to do not give that luxury. I would almost bet I could get better performance from a 300 Speer Gold Dot at impact over those ranges than i would from most any pointy SST/SW that can be shot from a ML. If we were to talk CF - then I could handle a Pointy Nosler or Barnes.
Granted the Pointy's have better ballistics but it is the performance at the POI that I looking for.
Just my thoughts - but then again I am old fashioned.
For myself only I am 200 yard shooter max - that is my self imposed limit. Next the chances of getting a decent 200 yard shot are really remote in Idaho - well where I hunt. I would bet my average shot over 40 years of hunting is 60 yards max.
I have absolutely no need to shoot a point type bullet from a ML unless it were a Nosler, Barnes, or and hopefully the Lehigh.
I need a bullet that will perform equally well from 20 yards to 200 yards at what ever velocity it has at the time of impact. The SST/SW and most other pointy bullets to do not give that luxury. I would almost bet I could get better performance from a 300 Speer Gold Dot at impact over those ranges than i would from most any pointy SST/SW that can be shot from a ML. If we were to talk CF - then I could handle a Pointy Nosler or Barnes.
Granted the Pointy's have better ballistics but it is the performance at the POI that I looking for.
Just my thoughts - but then again I am old fashioned.
08-07-2009, 08:19 PM
#7
Giant Nontypical
Thread Starter
Join Date: Nov 2005
Posts: 6,585
Sabot loader
well actually I have only shot at game at the 200yd + once, it was wide open field with no wind and the last afternoon of hunting season, and I dropped him on the spot with a Hawken side lock 54 cal and PRB. Under normal circumstances I get most of my game at bow range. What I do like to shoot at those kind of ranges is gongs and knock downs which I shoot for fun just like you do clay birds. I also like to play with numbers. Some one said a while back that the BC really does not make any difference unless you are shooting over two hundred yards when hunting and it bothered me because the amount of energy that the bullet has makes a difference even with a bullet that opens properly and a good hit. I assume that we all are good enough sportsmen to recognize our limits and not shoot shots where we know better except on the range where we can do it for fun on some kind of target that's not alive. Lee
well actually I have only shot at game at the 200yd + once, it was wide open field with no wind and the last afternoon of hunting season, and I dropped him on the spot with a Hawken side lock 54 cal and PRB. Under normal circumstances I get most of my game at bow range. What I do like to shoot at those kind of ranges is gongs and knock downs which I shoot for fun just like you do clay birds. I also like to play with numbers. Some one said a while back that the BC really does not make any difference unless you are shooting over two hundred yards when hunting and it bothered me because the amount of energy that the bullet has makes a difference even with a bullet that opens properly and a good hit. I assume that we all are good enough sportsmen to recognize our limits and not shoot shots where we know better except on the range where we can do it for fun on some kind of target that's not alive. Lee
08-07-2009, 09:26 PM
#8
Boone & Crockett
Join Date: Aug 2004
Location: Idaho
Posts: 11,703
Lee
Well that statement right there pretty much tells you how important ballistics are to 200 yards... BC really does not make that much difference, if the hunter can shoot. What is the BC of the 54 cal Round Ball? Could your pointy, high BC bullet done any better that. If you are doing that with a 54 cal PRB - then I should be OK with a .175 -.200 BC copper clad (or brass) bullet - but it should shoot to the target easier...
Shooting gongs, knock downs, and clay pigeons beyond 200 would be a good place for SST/SW's... but to expensive for me...
well actually I have only shot at game at the 200yd + once, it was wide open field with no wind and the last afternoon of hunting season, and I dropped him on the spot with a Hawken side lock 54 cal and PRB.
Shooting gongs, knock downs, and clay pigeons beyond 200 would be a good place for SST/SW's... but to expensive for me...
08-08-2009, 11:32 AM
#9
Giant Nontypical
Thread Starter
Join Date: Nov 2005
Posts: 6,585
Sabotloader
It sure makes a difference on knock downs. And I still say that a PRB has killing power way beyond the numbers myself and one of the popular people who thinks he knows a lot and tries to put down PRB had a disagreement about that. He supposed to be so good and when we shot off hand no supports of any kind allowed he was pitiful.
While I see your point I still believe it can make a difference, its like the difference between being hit with a wood stick which can kill you if it hits just right and a lead filled iron pipe which is not real sensitive to the angles and spots. I won't take an angle shot with a low BC bullet it has to be broad side. I have done a lot of hunting in the past with 250gr Gold Dots and they do a great job but if I ever need to take a long shot with one the animal with have to be standing still and broad side. Lee
It sure makes a difference on knock downs. And I still say that a PRB has killing power way beyond the numbers myself and one of the popular people who thinks he knows a lot and tries to put down PRB had a disagreement about that. He supposed to be so good and when we shot off hand no supports of any kind allowed he was pitiful.
While I see your point I still believe it can make a difference, its like the difference between being hit with a wood stick which can kill you if it hits just right and a lead filled iron pipe which is not real sensitive to the angles and spots. I won't take an angle shot with a low BC bullet it has to be broad side. I have done a lot of hunting in the past with 250gr Gold Dots and they do a great job but if I ever need to take a long shot with one the animal with have to be standing still and broad side. Lee
