Efficient Cartridges

[KSTiger]

Seeking some wisdom here.

Has anybody ranked typical hunting cartridges by their “efficiency”?

Thinking of measuring “efficiency” by the velocity per charge weight (fps/gr) of different cartridges that are being considered to hunt the same game. Thinking maybe using typical or average bullet weights per cartridge with expected muzzle velocity vs case capacity. Might be a way to measure energy in that same vain (for whatever that’s worth).

From a reloader’s perspective, you would think getting the most out of each grain of powder would be a good idea during these trying times.

Does anybody have any research to share on this?

 

[DJL2]

My opinion - MV is a poor measure. Energy is probably more appropriate, perhaps momentum if you prefer. Brian Litz actually covers this, now that I think about it. Really, when it comes down to it, there are a few things you're going to see:
1. powder is chemical potential energy waiting to get turned into KE and "waste"
2. efficiency in a pure sense is a measure of how effectively the chemical energy converts into KE
3. longer barrels for less wasteful powder burn are an advantage
4. matching powder burn rate to barrel length for more complete combustion is an advantage
5. efficiency and performance aren't the same thing
6. similar mass favors larger bores at the muzzle, more aerodynamic projectiles at range
7. shorter/wider powder columns tend to be more efficient for the same powder mass

If MV is really all you want, buy a .223 or .223 AI and be done with it. You won't find many cartridges that can rival 3000+ fps out of 25 ish grains of powder.

 

[762 ULTRAMAGA]

Seeking some wisdom here.

Has anybody ranked typical hunting cartridges by their “efficiency”?

Thinking of measuring “efficiency” by the velocity per charge weight (fps/gr) of different cartridges that are being considered to hunt the same game. Thinking maybe using typical or average bullet weights per cartridge with expected muzzle velocity vs case capacity. Might be a way to measure energy in that same vain (for whatever that’s worth).

From a reloader’s perspective, you would think getting the most out of each grain of powder would be a good idea during these trying times.

Does anybody have any research to share on this?

Why worry about it?
If you're a match shooter putting thousands of rounds through your rifle each season then yeah but otherwise here's what it boils down to

A 308 averages 45 grains /round or 320 rounds /lb
A 7 mag averages 65 grains/round or 213 rounds/lb
A hot 300 prc/30 Nos on the highest end uses 80 grains/ round or 177 rounds/lb

At an average cost if $32/lb
That's $100/1000 rounds for a 308
$150/1000 for a 7 mag
And $180/1000 for the hot 30 mags

Given the cost of everything else, and the scarcity of primers compared to the abundance of powders I can't see why it matters much

 

[menhaden_man]

223

 

[35WhelenAI]

Going with energy or even better yet, momentum, a 35 Whelen or AI version is very efficient when going for per grain of charge weight comparisons.

30-06 with a 60 grain charge under a 180 grain charge, at 2750 fps mv has 3022 ft/lbs and momentum of 70.61 lb ft/s.

35 Whelen with a 58 grain charge under a 250 grain bullet, at 2600 fps has 3752 ft/bs energy and momentum of 92.75 lb ft/s.

My 35 Whelen AI with 61 gr under a 200 gr TTSX at 2925 fps has 3799 ft/lbs energy and 83.52 lb ft/s. This load has better than you would expect trajectory for out to 400 yds (velocity is right at 2000 fps, don't want less for reliable expansion on this bullet, IMO). This isn't a long range rig as some guys think of long range around here, but delivers in spades on over a dozen elk and a few mule deer.

 

[hodgeman]

There are a lot of ways to gauge efficiency, some cartridges just do better than others.

Look at the cartridges commonly used in BR or PRS matches- stuff like the 6GT, 6.5CM, 6.5x47 Lapua, any of the BR cartridges...they sip powder and extract the most accuracy and performance from their cases.

For a hunting rifle, I'll just take a magnum 30 and flatten something.

 

[Maw7989]

30-338 Win Mag or 308 Norma use less powder and a shorter case but have a longer neck than 300 Win mag and get very close to the same muzzle velocity

 

[Middleofnowhere]

There are so many factors to choosing a cartridge. As 762Gunner pointed out, it’s easy to figure out how many rounds you can roll with a given amount of powder.

Using essentially the same 308 parent size case, you could choose a bunch of different calibers and compare downrange energy at different distances. For instance, the 308 Win case is used for at least the following:
243
260 Remington
7mm-08
308 Win
338 Federal
358 winchester

There are so many variables that you will ultimately be forced to own a bunch of different rifles LOL

 

[dirtytough]

Why worry about it?
If you're a match shooter putting thousands of rounds through your rifle each season then yeah but otherwise here's what it boils down to

A 308 averages 45 grains /round or 320 rounds /lb
A 7 mag averages 65 grains/round or 213 rounds/lb
A hot 300 prc/30 Nos on the highest end uses 80 grains/ round or 177 rounds/lb

At an average cost if $32/lb
That's $100/1000 rounds for a 308
$150/1000 for a 7 mag
And $180/1000 for the hot 30 mags

Given the cost of everything else, and the scarcity of primers compared to the abundance of powders I can't see why it matters much

Something is way off. Have you ever actually tracked how many rounds you get from 1lb of powder or done the conversion from grains to pounds?

The easiest I ever did to track was a 22-250 load with 34.8 grains of powder. 1lb =7000 grains. I barely got 200 loads from that 1 pound of powder. Not sure how you are getting 177 rounds of something using 80 grains out of a pound, or 320 rounds of something using 45 grains out of a pound.

Maybe my brand new bottle was half empty and 7000 grains doesn’t equal 1lb?

 

[762 ULTRAMAGA]

Something is way off. Have you ever actually tracked how many rounds you get from 1lb of powder or done the conversion from grains to pounds?

The easiest I ever did to track was a 22-250 load with 34.8 grains of powder. 1lb =7000 grains. I barely got 200 loads from that 1 pound of powder. Not sure how you are getting 177 rounds of something using 80 grains out of a pound, or 320 rounds of something using 45 grains out of a pound.

Maybe my brand new bottle was half empty and 7000 grains doesn’t equal 1lb?

Yeah that was a conversation error, so cost will be more per 1000 rounds but the same concept applies
You'll spend about $210 for 1000 rounds of powder for an anemic 308 sized case, and on the other extreme it'll cost about $320 for 1000 from one of the highest capacity magnums.
$110 still isn't much to fuss about

 

[ericwh]

Something is way off. Have you ever actually tracked how many rounds you get from 1lb of powder or done the conversion from grains to pounds?

The easiest I ever did to track was a 22-250 load with 34.8 grains of powder. 1lb =7000 grains. I barely got 200 loads from that 1 pound of powder. Not sure how you are getting 177 rounds of something using 80 grains out of a pound, or 320 rounds of something using 45 grains out of a pound.

Maybe my brand new bottle was half empty and 7000 grains doesn’t equal 1lb?

Yeah I was getting ready to post the same thing - looks like he was off by a factor of ~2. He said it with confidence though...

 

[ericwh]

You'll spend about $210 for 1000 rounds of powder for an anemic 308 sized case, and on the other extreme it'll cost about $320 for 1000 from one of the highest capacity magnums.
$110 still isn't much to fuss about

valid point.

 

[Lawnboi]

Why worry about it?
If you're a match shooter putting thousands of rounds through your rifle each season then yeah but otherwise here's what it boils down to

A 308 averages 45 grains /round or 320 rounds /lb
A 7 mag averages 65 grains/round or 213 rounds/lb
A hot 300 prc/30 Nos on the highest end uses 80 grains/ round or 177 rounds/lb

At an average cost if $32/lb
That's $100/1000 rounds for a 308
$150/1000 for a 7 mag
And $180/1000 for the hot 30 mags

Given the cost of everything else, and the scarcity of primers compared to the abundance of powders I can't see why it matters much

How are you coming up with these calculations. I wish I was getting 320 rounds a pound out of my 41.5 grain cartridge.

I’m not even at 300 rounds per pound on my 223.

 

[Stinky Coyote]

Seeking some wisdom here.

Has anybody ranked typical hunting cartridges by their “efficiency”?

Thinking of measuring “efficiency” by the velocity per charge weight (fps/gr) of different cartridges that are being considered to hunt the same game. Thinking maybe using typical or average bullet weights per cartridge with expected muzzle velocity vs case capacity. Might be a way to measure energy in that same vain (for whatever that’s worth).

From a reloader’s perspective, you would think getting the most out of each grain of powder would be a good idea during these trying times.

Does anybody have any research to share on this?

Not sure it will work out as you're thinking as you may eek out a bit more ft/lbs from something shooting a bigger fatter slug but that slug may fall on it's face 150 yards out the end of the barrel? So one has to make their list of parameters important to them before starting to find what's most efficient to them and it's a dynamic list available. Some of the options could be...

Max Distance Potential
Max Size Game
Minimum Sectional Density
Minimum Impact Velocity
Minimum Impact Energy
Minimum Bullet Diameter
Minimum Bullet Weight
Recoil Energy
Barrel Life
Time of Flight
Wind Drift
Factory Availability
MPBR (max point blank range)
Accuracy

I don't choose all of the above parameters and have maybe missed listing some but I do choose a good many of them. I always start with the bullets, then apply the range potential I want, then I can figure out the head stamp that will drive said bullet out to max distance and minimum fps impact thresholds without any extra fat.

The easier button to find the most versatile from that list above currently would to just look at the 21st century 6.5's with bullets in the 123-156 range as they run the highest SD's & BC's and extract the most from the powder burned in terms of terminal performance/distances, game it can take, recoil, barrel life, wind drift, time of flight, factory availability etc. They just do more of the above for the powder burned than the 20th century cartridges and very early 21st century (wsm) etc. Examples below...

The 6.5 Grendel with a 123 will give you the most from ~30 grains of powder, the 6.5 Creedmoor will give you the most of ~41 grains of powder and and 6.5 PRC ~59 grains. Each option giving you approx. ~200 yards further potential with both the CM & PRC giving higher SD & heavier bullets that fight wind better also but better for more 3rd class game.

6.5G 123gr at 95% factory rated velocity - 1800 fps lands at 450 yards, recoil energy in 8.5 lb rifle at 6.8 ft/lbs. SD .252, BC .506, barrel life is that of a .22lr

6.5CM 143 as above at 1800 fps lands at 650 yards, recoil 11.3 ft/lbs, SD .293, BC .625, barrel life - longer than anything but the Grendel.

6.5PRC 143 as above at 1800 fps lands at 825 yards, recoil at 17.9 ft/lbs, SD .293, BC .625, barrel life - as good as anything that will kill big game at 850 yards.

Niche ends; the PRC makes you eat a more manly 17.9 ft/lbs recoil energy so give up on the shootability for the smaller shooters and some barrel life. The Grendel gives up some SD/BC so just gets into the 3rd glass game bullet size and more suited to bulk of game being 2nd class but it's wins are unlimited barrel life and shootability for anyone with single digit ft/lbs recoil energy. It still does well inside 500 yards which will work for most.

The 6.5 CM however has no weak areas, it captures the majority of the categories the most equally, I can't think of anything that will touch it for near 41 grains of powder burned.

Anyway, hope that's a contribution to the topic. It's a dynamic one.

 

[z987k]

Ya, you have to define efficiency. Muzzle energy or downrange energy, because if it's just at the muzzle the big bores will win per grain of powder burned. But they loose really bad out past 4 or 500 yards.

 

[Pickettpuncher]

Why worry about it?
If you're a match shooter putting thousands of rounds through your rifle each season then yeah but otherwise here's what it boils down to

A 308 averages 45 grains /round or 320 rounds /lb
A 7 mag averages 65 grains/round or 213 rounds/lb
A hot 300 prc/30 Nos on the highest end uses 80 grains/ round or 177 rounds/lb

At an average cost if $32/lb
That's $100/1000 rounds for a 308
$150/1000 for a 7 mag
And $180/1000 for the hot 30 mags

Given the cost of everything else, and the scarcity of primers compared to the abundance of powders I can't see why it matters much

No way you’re getting 320 rounds at 45gr per round in a pound of powder. 7000/45= 155.555555. Before Biden took office you might could get powder that cheap but powder now is closer to $40/pound, with some of the more popular stuff over. That’s local prices, I’m sure it varies.

 

[canyonhunter47]

Ballistically speaking, I think this makes the most sense comparing within calibers, say: 7mm/08, 7 RM, 280 Rem, 280 AI (and SAUM, Weatherby, WSM, etc.). Same for the various 6.5’s, 308/30/300’s.

Using the 7mm’s as an example the 7 RM uses more powder over the 280 AI relative to it’s higher FPS

In general, I would suppose that short, fat cartridges pushing heavy-for-caliber bullets are more efficient at killing for the powder used per shot

 

[menhaden_man]

What I would probably do (if I cared to know the answer) is plot charge of a common powder (say Varget) on the x axis against energy on the y axis (which would account for bullet weight and velocity) across several calibers. You'd see a linear relationship and points above that line would represent "efficiency" so far as getting more energy than expected.

 

[Dead eye BT]

My totally unscientific choice here is the 7mm-08. Punches well above its weight class.

For example, I’m squeezing 49.0 grains of Big Game under a 140 TTSX for an average of 2880 FPS in my 7-08.

I get a sticky bolt lift with any more than 75.5 grains of Magnum (Barnes lists this as their recommended powder at 3199 FPS with 77.1) under a 140 TTSX for my 7mm RM. 75.5 averages 3010 FPS over my chrony. Maybe my 7mm RM has a slow barrel…. Either way, that’s a lot more burned powder and muzzle blast for a small gain in velocity and energy.

I’ve always considered the 7-08 to be very efficient. I also appreciate the softer muzzle blast. I could make similar comparisons with the 308 vs any of the 300 magnums, the 260 Rem or 6.5 man bun vs 264 Win Mag, etc. The hunting rounds burning 45-50 grains of powder can make a lot of velocity and energy per grain of powder.

 

[ramsdude47]

Another vote for 6.5 creed / 7mm-08