packgoatguy
WKR
Im sure variations of this topic have been beat to death... however I thought I would share the approach I took in picking a cartridge that will do the job on the game I intend to hunt.
Over the years, ive found various references to "rules of thumb" or even mathematical formulas to quantify and compare a bullet's ability to bring down a game animal quickly and humanely.
I decided I wanted to know the threshold for
1) what would give me ENOUGH bullet, without being overkill (wasting meat, too much recoil, etc)
2) kill as quickly as possible, and if necessary leave as much blood trail as necessary.
3) manageable recoil
4) High BC/wind bucking bullet options
4) and other factors including barrel life, factory ammo availability, etc.
Among the various rules of thumb, the 3 I found most impactful were:
1. energy on target ( ie, 1200 foot pounds for deer sized game and 1500 foot pounds minimum for elk or bigger game)
2. Velocity (1600 fps for minimum expansion velocity for many modern bullets, 2000-2200 fps for "hydrostatic shock effect")
3. KPS (Killing Power Score) to quantify bullet shape, diameter, sectional density, and penetrating power (ie a 12-20 KPS for deer sized game, 25-30 KPS for small elk sized game, 35+ KPS for big elk, moose, and up) Killing Power score is calculated as: energy (at the target yardage) x sectional density of the bullet x frontal area of the bullet.
E x SD x A = KPS...
But, instead of picking one or the other... I thought; why not use all three? So, I made a spreadsheet... I can share if you PM me.
My criteria was a cartridge that could take "big" elk at up to 600 yards. It needed to have
1) a minimum of 2000fps of retained velocity by the time it reached the target (with the advantage going to rounds that still were going 2200fps at the max yardage)
2) a minimum of 1500 foot pounds of energy at the target
3) a KPS score of 35 or more
Of course cartridge options like the 338LM or 300RUM would more than fit the bill... but I wanted to know the minimum.
At least for the 4000-8000ft of elevation where I typically hunt and shoot, the numbers favored the low end 30 cal magnums as a minimum threshold; ie 300 Win Magnum or 300 WSM. With pretty much any bullet choice, even out of shorter barrels and with low BC monolithic or bonded style bullets, the spreadsheet said I would still meet all three criteria at 600 yards.
Fast 7mm cartridges like 28 Nosler and 7WSM would also do the trick, but needed to be at the heavier end/ higher BC end of the bullet choice scale.
Considering I already have a bunch of 300 Win brass, the choice was for me was easy. With a brake on any of my 300 win rifles, even my kids can shoot them comfortably.
Basically, for me, the 300 win mag gives me everything I "need" for elk and under. Understanding that shot placement and then bullet construction are also important... if I know that my bullet is still carrying at least 2000fps, 1500ft pounds and has the killing power of a nearly a 44 mag at point blank range... then even I have always have enough velocity for bullet expansion, penetration through a rib, or even a margin of error if the shot isnt perfect.
Just for kicks and giggles, I ran the same numbers for "large deer and small elk" at 600 yards max range
1) a minimum of 2000fps at the target
2) a minimum of 1500 ft lbs
3) a KPS score of 30 or more
Dropping the KPS score to a 30KPS brought in the 280AI and the 7 Rem Mag.
For comparison with other popular cartridges: at 600 yards, my math shows
6.5 Creedmoor ELDX 2700MV,
2031fps target velocity
1310ft lbs Retained energy
21 KPS
308 WIN 178 ELDX, 2600MV;
1868 FPS velocity on target
1379 ft lbs retained energy
28 KPS
6.5PRC 143 ELDX 2960 MV
2253 FPS velocity on target
1612 ft lbs retained energy
26 KPS
For an excellent article of the KPS (killing Power Score), if you google it, you will find an editorial on the Chuck Hawks website.
For comparison:
At the muzzle,
.5 KPS
22 Mag pistol
5 KPS
9mm pistol
12 KPS :
223 rem 75g (rifle velocity)
10mm out of Glock 29
16KPS
G20 200gr Hard Cast 10mm
45 super
7mm-08 150gr at 1000 yards
20KPS
41 Mag
300blk
22kps
243 Win
24KPS
460 Rowland
6.5 Grendel
25 KPS
7mm-08 at 500 yards
37 KPS
6.5 CM (at the muzzle)
40 KPS
44 Mag 305 gr
60KPS
12 guage shotgun 1oz slug
70kps
30-06 at the muzzle
72KPS
458 socom
45/70
80 KPS
300 Win (at the muzzle)
126 KPS
500 S&W magnum 500gr
Over the years, ive found various references to "rules of thumb" or even mathematical formulas to quantify and compare a bullet's ability to bring down a game animal quickly and humanely.
I decided I wanted to know the threshold for
1) what would give me ENOUGH bullet, without being overkill (wasting meat, too much recoil, etc)
2) kill as quickly as possible, and if necessary leave as much blood trail as necessary.
3) manageable recoil
4) High BC/wind bucking bullet options
4) and other factors including barrel life, factory ammo availability, etc.
Among the various rules of thumb, the 3 I found most impactful were:
1. energy on target ( ie, 1200 foot pounds for deer sized game and 1500 foot pounds minimum for elk or bigger game)
2. Velocity (1600 fps for minimum expansion velocity for many modern bullets, 2000-2200 fps for "hydrostatic shock effect")
3. KPS (Killing Power Score) to quantify bullet shape, diameter, sectional density, and penetrating power (ie a 12-20 KPS for deer sized game, 25-30 KPS for small elk sized game, 35+ KPS for big elk, moose, and up) Killing Power score is calculated as: energy (at the target yardage) x sectional density of the bullet x frontal area of the bullet.
E x SD x A = KPS...
But, instead of picking one or the other... I thought; why not use all three? So, I made a spreadsheet... I can share if you PM me.
My criteria was a cartridge that could take "big" elk at up to 600 yards. It needed to have
1) a minimum of 2000fps of retained velocity by the time it reached the target (with the advantage going to rounds that still were going 2200fps at the max yardage)
2) a minimum of 1500 foot pounds of energy at the target
3) a KPS score of 35 or more
Of course cartridge options like the 338LM or 300RUM would more than fit the bill... but I wanted to know the minimum.
At least for the 4000-8000ft of elevation where I typically hunt and shoot, the numbers favored the low end 30 cal magnums as a minimum threshold; ie 300 Win Magnum or 300 WSM. With pretty much any bullet choice, even out of shorter barrels and with low BC monolithic or bonded style bullets, the spreadsheet said I would still meet all three criteria at 600 yards.
Fast 7mm cartridges like 28 Nosler and 7WSM would also do the trick, but needed to be at the heavier end/ higher BC end of the bullet choice scale.
Considering I already have a bunch of 300 Win brass, the choice was for me was easy. With a brake on any of my 300 win rifles, even my kids can shoot them comfortably.
Basically, for me, the 300 win mag gives me everything I "need" for elk and under. Understanding that shot placement and then bullet construction are also important... if I know that my bullet is still carrying at least 2000fps, 1500ft pounds and has the killing power of a nearly a 44 mag at point blank range... then even I have always have enough velocity for bullet expansion, penetration through a rib, or even a margin of error if the shot isnt perfect.
Just for kicks and giggles, I ran the same numbers for "large deer and small elk" at 600 yards max range
1) a minimum of 2000fps at the target
2) a minimum of 1500 ft lbs
3) a KPS score of 30 or more
Dropping the KPS score to a 30KPS brought in the 280AI and the 7 Rem Mag.
For comparison with other popular cartridges: at 600 yards, my math shows
6.5 Creedmoor ELDX 2700MV,
2031fps target velocity
1310ft lbs Retained energy
21 KPS
308 WIN 178 ELDX, 2600MV;
1868 FPS velocity on target
1379 ft lbs retained energy
28 KPS
6.5PRC 143 ELDX 2960 MV
2253 FPS velocity on target
1612 ft lbs retained energy
26 KPS
For an excellent article of the KPS (killing Power Score), if you google it, you will find an editorial on the Chuck Hawks website.
For comparison:
At the muzzle,
.5 KPS
22 Mag pistol
5 KPS
9mm pistol
12 KPS :
223 rem 75g (rifle velocity)
10mm out of Glock 29
16KPS
G20 200gr Hard Cast 10mm
45 super
7mm-08 150gr at 1000 yards
20KPS
41 Mag
300blk
22kps
243 Win
24KPS
460 Rowland
6.5 Grendel
25 KPS
7mm-08 at 500 yards
37 KPS
6.5 CM (at the muzzle)
40 KPS
44 Mag 305 gr
60KPS
12 guage shotgun 1oz slug
70kps
30-06 at the muzzle
72KPS
458 socom
45/70
80 KPS
300 Win (at the muzzle)
126 KPS
500 S&W magnum 500gr
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