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The Importance of Ballistic Coefficient When Selecting Ammo and Bullets |
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The importance of a bullet's exterior ballistic coefficient (BC)is sometimes overlooked when selecting a
new ammo or bullets for reloading hunting ammunition. The BC of a bullet has a significant impact on
trajectory, energy, and wind drift, especially at extended ranges associated with big game or varmint
hunting. Selecting a bullet with a high BC can give you a tremendous advantage in the field. It can make
the difference between a hit or miss, and also insure a quick, sure kill on big game.
For those of you who may be new to the term, BC is the ability of a bullet to overcome drag. (For a more scientific explanation, click here). Short, fat, flat nosed bullets have lower BC's than long, skinny, pointed
bullets. At close range, BC does not make much difference, but the longer the shot, the more BC
impacts the trajectory, retained energy, and wind deflection of a bullet. BC is usually stated in decimal
fractions with most modern hunting bullets falling between .180 and .550. Look for a bullet with a BC or
.400 or higher for flat trajectory and high energy at long range. All bullet manufacturers and some ammo
manufacturers provide the BC of their bullets on their web sites, on ammo ballistics charts and on their
web sites. Hornady and Remington provide BC's on their web sites. Bullet manufactures have them
listed on their web sites and in their loading manuals. For a rule of thumb, sharp pointed bullets tend to
have higher BC's. Look for the bullets in the table below in your favorite ammo brand to insure you are
getting bullets with high BC. If all this info is confusing, just look for the the load in your caliber with the highest energy at 250-300 yards.
Normally, when rifle calibers are compared, only muzzle velocity or muzzle energy are used to make the
comparison. Unless you plan to shoot all your game at under 10 yards, you have to look beyond muzzle
velocity and see how much energy your ammo is producing at the range you normally shoot game. My
shots are usually between 100 and 250 yards, so I want to know how well my bullet is performing at 250
yards. I can get this information using ammo manufacturers ballistic tables. For handloads I can use a computer program like Point Blank or the JBM online ballistics calculator.
Lets compare the trajectory, retained energy and drift of a couple of bullets of the same caliber, same
weight, same muzzle velocity but different shapes for the .308 Winchester. The Hornady .308 150 grain
round nosed bullet has a BC of .186 while the Hornady .308 150 grain SST pointed boat tail bullet has a BC of .415.
Below are the data for those two bullets. Look at the dramatic difference in performance throughout the
trajectory of the bullet, especially at extended ranges. The SST bullet has almost twice the energy of the
round nosed bullet at 300 yards, and the wind drift is only 1/3 as much. Drop is 50% more with the round
nosed bullet. To get the 300 yard performance of the round nosed bullet up to the performance of a
pointed nosed bullet, you would have to increase the muzzle velocity to 3700 fps! Even a 300 Ultra-mag
is 400 fps short of that velocity. So, how important is bullet selection? If your hunting buddy is shooting a
300 magnum with round nose bullets, and you are shooting a 308 Winchester using Hornady ammo with
SST bullets, who is really holding the "real" magnum? When shooters only look at advertised muzzle
velocity, instead of down range retained energy, they can really be fooled about the "power" of their rifle.
Hornady .308 Winchester 150 grain Round Nose bullet
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Range
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Velocity
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Energy
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Momentum
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Drop
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Windage
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(yards)
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(ft/sec)
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(ft-lbs)
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(lbs-sec)
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(inches)
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(inches)
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0
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2817.0
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2643.0
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1.88
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-1.5
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-0.0
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100
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2342.7
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1827.8
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1.56
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-0.0
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1.9
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200
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1919.4
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1226.9
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1.28
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-4.9
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8.1
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300
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1552.5
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802.7
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1.03
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-19.4
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20.1
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400
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1263.5
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531.7
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0.84
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-48.5
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39.5
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500
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1079.3
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388.0
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0.72
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-99.2
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66.5
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Hornady .308 Winchester 150 grain SST pointed boat tail bullet
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Range
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Velocity
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Energy
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Momentum
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Drop
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Windage
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(yards)
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(ft/sec)
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(ft-lbs)
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(lbs-sec)
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(inches)
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(inches)
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0
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2807.6
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2625.4
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1.87
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-1.5
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-0.0
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100
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2588.5
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2231.5
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1.72
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-0.0
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0.8
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200
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2380.8
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1887.7
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1.59
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-3.7
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3.3
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300
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2183.5
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1587.8
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1.45
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-13.6
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7.7
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400
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1995.3
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1326.0
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1.33
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-30.7
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14.3
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500
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1818.2
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1101.0
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1.21
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-56.6
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23.3
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Most bullet and ammo manufacturers publish ballistics tables for their products. Some manufacturers, like Remington, have online charts that let you compare down range energy, bullet drop, and wind
deflection. A friend of mine inherited a Remington 30'06 and several boxes of 180 grain round nose ammo.
He asked me to help him get the rifle checked out and zeroed for deer season. I asked him why he
chose that ammo and he told me it came with the gun. I suggested he change the ammo before we
zeroed the rifle and he asked me why. So we went to the Remington ammo chart to compare available
ammo. I compared his ammo with with another Remington load and the results are listed below. Look at
the retained energy figures below and tell me which you would rather be shooing when that once in a lifetime buck steps out in the open at 250 yards!
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Remington 30'06 180 grain vs. 150 grain ENERGY (ft-lbs) comparison
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Cartridge Type
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Bullet
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Muzzle
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100
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200
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300
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400
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500
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Premier AccuTip
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150 ABT
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2820
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2403
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2037
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1716
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1436
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1193
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Remington Express
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180 SP CL
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2913
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2203
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1635
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1192
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859
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625
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Most hand loaders realized the difference in bullet shape years ago and took advantage of great bullets
like the Nosler Ballistic Tip. Now hand loaders and factory ammo shooters both have a great selection of bullets with great ballistic coefficients.
First, lets look at some of the bullets with the best ballistic coefficients, and then find which ammo
companies give you the great bullets in factory ammo. Click on the Bullet below for detailed information.
Bullets w/high Ballistic Coefficients
Cost of Box of 30'06 ammo for each bullet type
Hand loaders can pick any of the bullets above, but you may be surprised how many choices the ammo
manufactures give you today in factory ammo. Included in the table above is the cost of a box of 30'06 ammo with each bullet.
Remington give you several choices including the new Accu-Tip bullet, which is a bonded core version of
the Nosler Ballistic Tip. They also still load their old Bronze point bullet that was way ahead of its time
with a core lock and sharp bronze point. The Swift Scirocco bullet is also available from Remington. Quite a list of great bullets from Remington.
Black Hills loads two bullets with high BC's. The Barnes X bullet and the Nosler Ballistic Tip.
Winchester and Nosler teamed up a few years ago to develop the Combined technology bullets. One of
these is a Nosler Ballistic tip coated with Winchester Lubaloy. I don't see the purpose but it does look
pretty cool with bright chrome cases and black bullets. I can attest that they perform very well.
Federal gives us a host of choices with the Sierra Game King, Nosler Ballistic Tip, Barnes X bullet, as
well as Speer & Sierra Varmint bullets.
PMC loads Barnes X bullets in their gold line of ammo and Sierra bullets in their Silver line of ammo.
Hornady gives you custom ammo you can not get anywhere else using their own brand of bullets. Their
boat tail soft point and SST bullets have very high BC's. A plus for Hornady is that the ballistic data is
printed right on the box. I have shot two large Wild Boars and six deer this year with the Hornady SST
bullet in my 308 Winchester and every one when down in their tracks.
I hope this helps when you are looking for the best bullet for your hunting situation. BC is not the only
thing to consider when you buy ammo, but it is a very important piece of the ammo puzzle. High BC
usually means High Performance so do your homework before you buy the next box of ammo and make sure your rifle can be all it can be.
Chester
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