The most efficient hunting cartridges

This is the basics physics : bullet and propellant energy is Ebp = mbp * vbp * vbp / 2 = pbp * pbp / (2 * mbp) where
so pbp * pbp = Ebp * mbp * 2

Ebp = bullet and propellant energy
mbp = bullet and propellant mass
pbp = momentum = m * v
vbp = bullet and propellant velocity

Bullet + propellent momentum = Rifle free recoil momentum
pbp (bullet and propellant) = pr (rifle free recoil)
Rifle free recoil energy is also Er = mr * vr * vr / 2 = pr * pr / ( 2 * mr ) where pr = pbp so

Er = pbp * pbp / (2 * mr) = Ebp * mbp * 2 / (2 * mr) = Ebp * mbp / mr

This is the important point Er (free recoil energy) is proportional to mbp (mass of bullet and propellant) for any constant Ebp (roughly proportional to projectile energy) and mr (mass of rifle).
This means that for a given projectile energy level (Ebp) and a rifle (mr), free recoil (Er) is proprotional to propellant and projectile mass (mbp)

So in a 9lb rifle and with say 2500ft-lbs of muzzle energy, a 75gr cartridge will produce half the free recoil of a similar energy 150gr cartridge.
In simpler terms, a 2500ft-lbs 80gr 243gr hot load produces half the recoil of a 150gr mild 308 Win load.
(About light bullet loads, the "work" but fail is real life since this implies low bullet sectional density which means low penetration one medium-large game.)

Alex
 
AlexF said:
This is the basics physics : bullet and propellant energy is Ebp = mbp * vbp * vbp / 2 = pbp * pbp / (2 * mbp) where
so pbp * pbp = Ebp * mbp * 2

Ebp = bullet and propellant energy
mbp = bullet and propellant mass
pbp = momentum = m * v
vbp = bullet and propellant velocity

Bullet + propellent momentum = Rifle free recoil momentum
pbp (bullet and propellant) = pr (rifle free recoil)
Rifle free recoil energy is also Er = mr * vr * vr / 2 = pr * pr / ( 2 * mr ) where pr = pbp so

Er = pbp * pbp / (2 * mr) = Ebp * mbp * 2 / (2 * mr) = Ebp * mbp / mr

This is the important point Er (free recoil energy) is proportional to mbp (mass of bullet and propellant) for any constant Ebp (roughly proportional to projectile energy) and mr (mass of rifle).
This means that for a given projectile energy level (Ebp) and a rifle (mr), free recoil (Er) is proprotional to propellant and projectile mass (mbp)

So in a 9lb rifle and with say 2500ft-lbs of muzzle energy, a 75gr cartridge will produce half the free recoil of a similar energy 150gr cartridge.
In simpler terms, a 2500ft-lbs 80gr 243gr hot load produces half the recoil of a 150gr mild 308 Win load.
(About light bullet loads, the "work" but fail is real life since this implies low bullet sectional density which means low penetration one medium-large game.)

Alex
Click to expand...

yes, a 270 will kill a moose
 
flashman2 said:
Buddy, unless you got a better system than me for doing all those calculations, my hat is off at the amount of work that's gone in here.

The big surprise for me was how well the .308 and .303 stacked up.
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I worked at it on and off for a while. It started as a quick comparison, then snowballed. Figured I should post it up on CGN, create some discussion if nothing else
 
todbartell said:
I worked at it on and off for a while. It started as a quick comparison, then snowballed. Figured I should post it up on CGN, create some discussion if nothing else
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Overall, :) a very good and informative post. You put in a commendable effort to say the least. There are a few on your list that are applicable to what I have in the safe, ;) but there are quite a few more that are not. That being primarily because much of what I have available, :) are a little off of centre. Examples of what I'm getting at are;
- 219 Donaldson Wasp
- 7x61S&H
- 308 Norma Mag
- 348WCF
- 358 Norma Mag
To mention a few :) .
Thanks again,
:cheers:
Johnn
 
flashman2 said:
303 Brit 174 gr SPBT @ 2500 fps
42.0grs powder
BC .470
Recoil = 16.5
500y energy = 1147
Ft lb bullet energy per ft lb recoil = 69.5

That puts the classic 174 grain load at fifth place in the top 10... interesting.
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I got :

303 Brit 180gr Sierra Prohunter @ 2500 fps (RL26, RL17, RL16, RS Hunter, CFE223, Win760)
45.8grs powder
BC .411
Recoil = 17 ft lbs
500y energy = 1047
Ft lb bullet energy per ft lb recoil = 61.6

using more "old school" or traditional powders :

303 Brit 180gr Sierra Prohunter @ 2440 fps (Win760, IMR 4895, Win748, IMR 3031, IMR 4320, BLC-2)
40.6grs powder
BC .411
Recoil = 15 ft lbs
500y energy = 989
Ft lb bullet energy per ft lb recoil = 65.9


Now, need to somehow factor in steel butt plate from a Lee Enfield into the formula :cool:
 
flashman2 said:
Wow. I just did the .303 Brit and now I appreciate how much work went into this!

Anyway....

303 Brit 150gr SP @ 2700 fps
44.0grs powder
BC .361
Recoil = 15.5
500y energy = 932
Ft lb bullet energy per ft lb recoil = 60.1

303 Brit 174 gr SPBT @ 2500 fps
42.0grs powder
BC .470
Recoil = 16.5
500y energy = 1147
Ft lb bullet energy per ft lb recoil = 69.5

That puts the classic 174 grain load at fifth place in the top 10... interesting.
Click to expand...

Modern rifle the 303 is the same as the 308. Case capacity is virtually identical.
 
todbartell said:
I got :

303 Brit 180gr Sierra Prohunter @ 2500 fps (RL26, RL17, RL16, RS Hunter, CFE223, Win760)
45.8grs powder
BC .411
Recoil = 17 ft lbs
500y energy = 1047
Ft lb bullet energy per ft lb recoil = 61.6

using more "old school" or traditional powders :

303 Brit 180gr Sierra Prohunter @ 2440 fps (Win760, IMR 4895, Win748, IMR 3031, IMR 4320, BLC-2)
40.6grs powder
BC .411
Recoil = 15 ft lbs
500y energy = 989
Ft lb bullet energy per ft lb recoil = 65.9


Now, need to somehow factor in steel butt plate from a Lee Enfield into the formula :cool:
Click to expand...

I guess the difference there is the 180 PH is flat base, compared to a BT pill which I was using. Heck, Sierra lists their 174 MK at .499 which is even a fair bit higher than what I used. 42.0 of Varget gives you an easy 2500 fps also which brings the recoil number down a bit from 45.8 too. I was using the same atmospheric inputs with standard pressure since I didn't see pressure listed.

The hard butt I don't mind as much as getting the back of my hand in my nose with that stock if I'm careless :p
 
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Gatehouse said:
Modern rifle the 303 is the same as the 308. Case capacity is virtually identical.
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Yup. Just interesting to see the numbers this way. I mean if you asked me "what's. 303 most comparable to?" I'd say .308, but seeing how the numbers work in the energy vs recoil example is interesting to me.
 
Eagleye said:
You are missing the point entirely. In a modern rifle you can load the 7x57 to the same pressures as the 7-08. At the same pressures, because the 7x57 has a bit more capacity, it will
be equal to or slightly faster than will be the 7-08. If you push the 7-08 over max, you will be into 70K+, where you do not want to go. D.
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Ok, true that, true that - I should have qualified it to exclude +P hand loads.

In any case, machts nichts to me, the 7x57 is one of my all time faves... I wouldn't own a 7-08 if it wasn't for shooting 7x57.
 
Wildcards!

.45-70 black powder load...

.45-70 535gr Postell @ 1150 fps
70grs powder
BC .402
Recoil = 17.2 ft lbs
500y energy = 955 ft lbs
Ft lb bullet energy per ft lb recoil = 55.5

Beats 150 gr .30-06??? Colour me surprised.

.416 Rigby 400gr @ 2400 fps
90grs powder
BC .319
Recoil = 78.8 ft lbs
500y energy = 1642 ft lbs
Ft lb bullet energy per ft lb recoil = 20.8

Oof.

If you make it a more realistic 10lb rifle it's 26.1
 
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Buckmastr said:
Does my hunting cartridge become more efficient if I put a muzzle brake on my gun?
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Simple answer is NO.

While the recoil is an interesting piece of information, it really has nothing to do with a cartridge's efficiency.
Efficiency of the cartridge is determined by the amount of velocity and energy that is produced per grain of powder burned.
If you are looking at retained velocity and energy numbers, drop and wind drift out to 500 yards, then this is going to be a result of the bullet's BC; the higher the BC, the higher the efficiency of the bullet, as this determines retained velocity and therefore energy.
If you are looking at the cartridges effectiveness on game, then you also want to look at the SD; the higher the SD, the better the efficacy (penetration capabilities) of the bullet, provided that it retains sufficient velocity and energy when it arrives on target to expand and penetrate to the vitals, given proper shot placement.

A more important point that is not really mentioned in this thread, is the length of barrel and the percentage of powder burned to produce the velocity listed. If the barrel is too short and not all of the powder is burned in the barrel, then it is wasted, and reduces the efficiency. I know QuickLoad provides this data on its reports, but I do not have, so cannot look it up. Longer barrels tend to provide more velocity, which in turn will improve efficiency by producing more velocity and energy per grain of powder burned.
 
^ not the discussion we're having. TB was pretty clear about what he defined as efficiency. The issues you raise are another discussion entirely.
 
flashman2 said:
^ not the discussion we're having. TB was pretty clear about what he defined as efficiency. The issues you raise are another discussion entirely.
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And yet in post #85, TB stated that his intent was create discussion. This is directly related to the discussion on cartridge efficiency. Just adding to the discussion. As a student of ballistics and engineering, I am interested in his findings as I stated earlier in this thread, as I have also done a similar exercise to his. Not trying to disrespect his conclusions or derail the discussion.

But if your opinion or definition of cartridge efficiency is different than mine, then so be it. We can agree to disagree on how we read the OP's intent and statement.
Wasn't looking to start an altercation or disrespect your, or anyone else's, opinion, knowledge or experience.
 
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