Forums » Ammunition » Ballistic Coefficient Calculator Discussions and arguments about caliber types, ballistics, ammo loads, handloading, and reloading.
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Hey Guys,
I prefer the .40 S&W too as it is close enough to the .45 in knock down.
Your point is well made Belt. A .22 in the eye is going to get the job done while a 9mm in the shoulder or belly may not. However I respectfully disagree that the numbers don't mean much. The target (say, the head of a perp) is not the object of the study, it is the knock down capability of the bullet. A .22 in the shoulder is not going to knock anyone down, but a .45 or .44 mag or even the .40 certainly will. This knock down coefficient had nothing to do with the lethal ability of the bullet. There are more civilians killed every year .22's than any other round.... more »« less
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What round are you using BB? I'm currently using 180gr Winchester Ranger T's and can't reach 1000 fps with it. Excellent ballistics with this stuff with the average 950fps it delivers.
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I kinda like my .40 still. Using your method my .40 S&W still rates a 12 and it delivers 490ft lbs at the muzzle while traveling over 1000fps.
or how about the .460 at 30!!! I'll admit though I am definitely still a 45 acp fan as well.
I feel bad for the .380 guys, best I could get is a 5.2 and the 9mm a mere 7.0!
As we all know, these numbers truly don't mean a whole lot. There are too many other factors and variables that can change any one factor in the real world.
IMO this method is is not somthing to rely on unless all your shooting is FMJ bullets into ballistic gel.
I will however agree it's good if one wants an idea of what a caliber is potentially capable of compared to a different caliber, but then again that was the whole point wasnt it! lol... more »« less
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Gun Test Magazine came up with a interesting theory.
How many of you think that the 85 grain 7.62 x 25 Tokarev (511 ft/lbs energy delivered) is as good a round as the 230 grain .45 acp (371 ft/lbs energy delivered)?
Gun Tests pointed out the obvious problem with ballistics of this nature and offered a solution. To determine knock down rather than energy delivered use this formula instead.
Diameter bullet (in caliber) x grain of bullet weight x ft/sec at whatever distance desired to test as long is it is the same for all rounds tested, divided by constant of say 7000 = knock down coefficient.
Using this forumla you will find the difference between the 511 ft/lbs of energy of the speedy 7.62 x 25 and the 371 ft/lbs of the venerable .45.
.45 acp: .45 inches x 230 grains x 853 ft/sec at muzzle / 7000 = 12.6
7.62 x 25: .30 inches x 85 grains x 1647 ft/sec at muzzle / 7000 = 5.99
THAT dear friends is the difference between knock down power and ballastics. The Tokarev offers more than 25% more energy delivered, but is less than half as good a round for knock down compared to the slowfooted .45.... more »« less