Marlin Firearms Forum banner

1 - 20 of 34 Posts

·
Premium Member
Joined
·
1,409 Posts
Discussion Starter · #1 ·
On the website, http://chuckhawks.com/rifle_killing_power_list.htm is a very interesting formula on killing power of different rifle cartridges. Chuck Hawks who is one of our most prestigious gun writers and theorists has come up with his formula for rifle cartridge power. His calculation is to take energy at 100yds (which is easy to come by) and multiply it times sectional density and then again by cross-sectional area. I ran a couple of calculations of this formula and thought to myself what about hunter error, animal toughness, time of day if you put in an factor for these you would have to do it for all cartridges so the result would stay the same.
Here are some of his killing power calculations.

.243Win (100gr @ 3600fps) = 10.1
.270Win (150gr @ 2850fps) = 37.4
7mm Rem Mag (150gr @ 3110fps) = 44.8
30-30 Win (170gr @ 2200fps) = 25.4
308Win (180gr @ 2620fps) = 46.2
30-06 Spg (220gr @ 2410fps) = 54.6 *
.300 Win Mag (180gr @ 2960fps) = 59.5
.338 Win Mag (250fr @ 2650fps) = 94.8
35 Whelen (200gr @ 2675fps) = 56.4
.375 H&H (270gr @ 2690fps) = 106.2
35Rem (200gr @ 2080fps) = 38.8 *
.444 Marlin (265gr @ 2325fps) =63.4
45/70 Gov (405gr @ 2000fps) = 125.8 *
450 Marlin (350gr @ 2100fps) = 88.9
.458 Win Mag (500gr @ 2090fps) = 217.3

* These were my calculations based on using his formula, the rest are Chuck Hawks . One real interesting comparison is the 30-30 vs the .35rem. Another interesting one is the 45/70 vs the .375 H7H. But all in all it is an interesting chart for comparison I didn't put down all the calibers as the list would get to long. One amazing thing is the 30-06 and the 45/70 are both about 100 years old and they keep hanging in there and are still keeping up with modern day rounds. So the more things change the more they stay the same. To me the list looks realistic and is easy to use for comparison data but is not scientific as Chuck Hawks quotes.

fknipfer
 

·
Registered
Joined
·
2,216 Posts
This is really neat, and as you said, fknip, it looks realistic and usable. Wish there was more data for the .444.

SS
 

·
Premium Member
Joined
·
1,409 Posts
Discussion Starter · #3 ·
There are not a whole lot of rifle bullets in the .444 Marlin, a lot of pistol bullets so it is hard or impossible to make a calculation.

fknipfer
 

·
Registered
Joined
·
41 Posts
First of all, hello, I have enjoyed lurking on here for a while.

Just a comment on that formula. Isn't sectional density just weight divided by frontal area? So his formula is actually just energy times weight. And energy is just mv^2, so his formula is m^2v^2 = (mv)^2 or just momentum squared. I.e. his ranking is purely based on momentum.

Have I missed something? If not, it's probably good formula for metallic silhouette and that's about it...
 

·
Premium Member
Joined
·
1,409 Posts
Discussion Starter · #5 ·
Russel,

My understanding of the formula is Energy @100yds X SC X Sq inches of the frontal part of the bullet. Maybe I missed something. He has a website were he explains the formula. He states this is only for comparison only and looking up and down his chart it looks pretty good. I would like to know after you look at his website what you think. His website is on the first post of this thread.


fknipfer
 

·
Registered
Joined
·
41 Posts
Thanks yeah I did look at it ... what I'm trying to say is I think that formula just comes out to be momentum squared (in some funny units)

energy x SD x A = mv^2 x m/A x A = m^2v^2 = (mv)^2

Or if you like numbers better than algebra, use this formula:

bullet weight (gr) x velocity (fps) / 70890

the square the result, i.e. multiply it by itself, and you get the same numbers he has on the table without needing to know anything about the SD or frontal area of the projectile.
 

·
Registered
Joined
·
422 Posts
Interesting for comparison but looks like a bunch of hocus pocus to me. I'm no ballistics expert but the formula simply makes big and fast bullets more impressive numerically than slower and lighter bullets.

It all comes down to shot placement. A heart shot deer with a 458 isnt going to die any quicker than an identically heart shot deer with a 30-06, 30-30, 243, whatever...........

Plenty of large animals have been killed with 22LR. Doesn't make it an effective killer or anything like a recomended killer but, for example, you don't need a 458 to kill something "better."

Still, its interesting to play with the numbers.
 

·
Administrator
Joined
·
23,798 Posts
The only comparison that I can think of for "deader" is deader than a doornail. Dead is Dead whether with a Chuck Hawks formula, or two 22s from a hit man.
 

·
Premium Member
Joined
·
1,409 Posts
Discussion Starter · #9 ·
I didn't mean to stir a hornets nest, but maybe a better term for his forumula might be striking momentum, or just striking power. Thats all I have to say on the subject.

fknipfer
 

·
Registered
Joined
·
3,073 Posts
I enjoy going to Chuck Hawks' site ever so often. It provides good recreational reading and much of what is offered squares with my own field experience.

However, when it comes mathematical formulae to calculate killing power, etc. my cynical/practical gene starts to quiver. I feel the same way about the endless arguments over batting averages and whether Ty Cobb was a better hitter than Ted Williams, etc., etc., yawn...

It's harmless fun and an honored pasttime. But the proof is in the field, and none of us will ever live long enough to (legally) take enough game to come to any definitive conclusion with practical significance about relative killing power.

Oh, isn't that what Swany and GLC already said? Sorry, I must have gotten too much sleep last night. :shock:

Let the fat chewing (re-) commence! :D :D :D :wink:

PS -- Welcome aboard, Russell.
 

·
Premium Member
Joined
·
14,841 Posts
WyoStillhunter,

Looks like 3 sound opinions to me sir. :wink:

Dave 8)
 

·
Registered
Joined
·
41 Posts
I agree --- but if you're going to make your own formula you should at least make it give different answers to everyone else's :lol: . Ok, here's mine

energy x momentum / velocity^3 / bullet weight^2

that should keep everyone happy -- it says they're all equal 8)
 

·
Registered
Joined
·
129 Posts
The .450 can be loaded heavier and faster than the .45-70, they put a low load there for the 450, and a heavy load to he 45-70. thats not a good camparison, its like comparing apples to oranges.
 

·
Registered
Joined
·
275 Posts
Hey guy's. Has anyone tried to recalculate his number results using his formula. I have tried and am consistantly off by a factor of about 1.2 (my answer is 1.2 times his). If so any you get his numbers, I would like to know where I am off.
 

·
Premium Member
Joined
·
12,094 Posts
981tman said:
The .450 can be loaded heavier and faster than the .45-70, they put a low load there for the 450, and a heavy load to he 45-70. thats not a good camparison, its like comparing apples to oranges.
You might get some different opinions to that statement. I'd say theyre apples & apples or oranges & oranges, you pick, but for all intents & purposes theyre the same with most folks giving the 45/70 a slight edge because of greater capacity. Some manuals reflect this & some dont but I feel its safe to say those that dont do so because of the weaker 45/70 actions out there. :)
 
G

·
981tman said:
The .450 can be loaded heavier and faster than the .45-70, they put a low load there for the 450, and a heavy load to he 45-70. thats not a good camparison, its like comparing apples to oranges.
NOT SO.

Sorry if direct is disconcerting, but that is false information.
 

·
Registered
Joined
·
275 Posts
Figured out my problem with my computations using the Hawks formulas.

1) The first one given is for a 243 Winchester 100 gr bullet at 3600 fps.
This is a typo. On the Hawks site the first one is a 223 WSSM with a 64 gr bullet at 3600 fps.

2) Hawks velocity figures are muzzle velocity not 100 yd velocity. You have to figure 100 yd velocity and plug that into the formula.

I am still convinced that this Hawks formula is a complicated way to just compare momentums. I will look into this when I have time.
 

·
Registered
Joined
·
275 Posts
I found the time and wrote a program to calculate the Hawks value for his given data (on his web site). I then had the program calculate the momentum of the bullet and squared it. No matter what data of his run through my program the result was the same, his value was the square of the momentum multiplied by the SAME constant for all of the cartridges and bullets.

Since the major fight over killing power has been between the momentum boys (big and slow) and the speed junkies (kenetic energy) his value is just the momentum method in disguise. His formula takes in weight, velocity, and area, but by use of his formula the area is canceled out in the computation leaving only weight and velocity which is the definition of momentum.
 

·
Premium Member
Joined
·
12,094 Posts
Isn't momentum just another way to say kinetic energy?
I hear much more argueing over these 2 words in a couple archery forums I visit than on gun boards but still get wrapped up trying to figure a difference.
Kinetic energy is expressed in FT/LBS usually, how does a person express momentum? Something that has little kinetic energy will have little momentum & vica versa I think. Kinetic energy exists in an object because it has momentum & momentum matters because the object in question carries kinetic energy. I always seem to conclude theyre 2 words expressing the same basic idea.
If theres a difference please explain. :?
 
1 - 20 of 34 Posts
Top