Can you get something for nothing?

I think the manufacturers advertised velocity vs real world velocity also plays a roll. I watched a video on yt about the complaints shooters had about the 7mm PRC hornady loads being below advertised. the reason given was the original powder used suddenly became unavailable so they had to switch to a different powder and chose one that gave the most consistent preformance instead of the highest velocity.
 
Hand Skills said:
Indeed, though the mass of powder plays into the equation as well. It's added to the mass of the bullet,

So if you have a 150gr bullet and 65gr of powder, that's 215gr of total mass

150gr bullet and 45gr of powder is 195gr.

If velocity is equal, and rifle weights are equal the 50gr load will have almost 10% less recoil.

You pay a much higher price in recoil for 10% more velocity though.

Energy correlates directly with Mass

Energy correlates to the SQUARE of velocity (V²).

To further muddy the waters;

I think there is more to recoil than just ft-lbs though. When it comes to felt recoil, the impulse (lb-sec) plays into it as well.
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That's correct. But I can't think of any examples where a 65gr powder loading will have the same velocity as a 45gr load, using the same bullet at the same pressure.
 
jethunter said:
That's correct. But I can't think of any examples where a 65gr powder loading will have the same velocity as a 45gr load, using the same bullet at the same pressure.
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Exactly.

Was listening to one of the Vortex Nation cartridge talks podcasts and one of the guys was bad-mouthing the 7 rem mag because it did the same thing as a .30-06 “only with more powder and a belt”
But then I go look at the load data again and the 7mm is outpacing the .30-06 by up to 100 fps. So yes, it is possible for the two cartridges to push a 150gr at the same speed, but if that’s not maximum performance for each one then it’s a bit of a moot point.
 
Hand Skills said:
Indeed, though the mass of powder plays into the equation as well. It's added to the mass of the bullet,

So if you have a 150gr bullet and 65gr of powder, that's 215gr of total mass

150gr bullet and 45gr of powder is 195gr.

If velocity is equal, and rifle weights are equal the 50gr load will have almost 10% less recoil.

You pay a much higher price in recoil for 10% more velocity though.

Energy correlates directly with Mass

Energy correlates to the SQUARE of velocity (V²).

To further muddy the waters;

I think there is more to recoil than just ft-lbs though. When it comes to felt recoil, the impulse (lb-sec) plays into it as well.
Click to expand...

I don’t think I buy the “weight of the powder” part of the equation…

At the end of the day, we’re bound to Newton’s 3rd law, and if a bullet leaves the barrel carrying 3000ftlbs of energy, then the bolt action rifle will travel in the opposite direction, also carrying 3000ftlbs of energy. The powder that was burned to achieve these two opposite motions was burned while pushing in both directions, so it’s original weight is no longer a part of the equation.

Thankfully, energy doesn’t hurt. Speed does. (A big steel hauler traveling at 1mph has 50 times more energy than a 100mph fast ball, but with one you could hold your hand out and let it slowly impact it while barely feeling it, whereas the fast ball hand is gonna be sore for a week.) A heavy rifle and a light weight rifle will both be carrying 3000ftlbs of energy, but the lighter rifle will recoil FASTER, which is what “hurts” more.
 
yidava25 said:
Over the years, but especially lately with the new PRCs, Creedmoors, Noslers, etc., I’ve heard people claim that cartridge X will do the same thing as cartridge Y only with less powder and/or less recoil. Usually said advantages are claimed to be the result of “efficient case design” or some such scientific breakthrough.
I don’t get it, and I haven’t ever seen an example of it in a reloading manual or in my own real world chronograph experiences.
Can someone demonstrate a case where, for example, they can push a 180 gr .30 cal bullet at 3000 fps using 80 grains of powder, where another cartridge will duplicate that performance with either more or less powder?
Having owned and loaded for a 6.5-300 Wby I’m perfectly aware of the phenomenon of diminishing returns (namely having to burn a lot more powder for a small increase in velocity) but that’s not what I’m talking about.
Also the recoil thing… just the other day I heard a guy describe how his 7 RM could hang with a 28 nosler but with much less recoil… isn’t recoil calculated using bullet velocity, bullet mass, and rifle mass? How then could you possibly have an equal action causing a lesser reaction?
Or is there a book I need to read to catch up with everyone…
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On recoil, there IS one free lunch: Semi autos.

If the bullet goes north with 3000ftlbs of energy, then the rifle has to go south with 3000ftlbs of energy, UNLESS we steal some of that energy for other tasks.
 
kodiakjack said:
On recoil, there IS one free lunch: Semi autos.

If the bullet goes north with 3000ftlbs of energy, then the rifle has to go south with 3000ftlbs of energy, UNLESS we steal some of that energy for other tasks.
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I’ve never tested it with a chrony but don’t you lose velocity with the same load in a gas gun vs a different action?
 
kodiakjack said:
I don’t think I buy the “weight of the powder” part of the equation…

At the end of the day, we’re bound to Newton’s 3rd law, and if a bullet leaves the barrel carrying 3000ftlbs of energy, then the bolt action rifle will travel in the opposite direction, also carrying 3000ftlbs of energy. The powder that was burned to achieve these two opposite motions was burned while pushing in both directions, so it’s original weight is no longer a part of the equation.
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It's absolutely part of the equation -- More powder, more gas, more pressure, all else being equal.
The only way it wouldn't be a factor is if the pressure at the muzzle as the bullet is leaving the barrel was zero.

Think of a blow gun on the end of an air hose.
 
kodiakjack said:
I don’t think I buy the “weight of the powder” part of the equation…

At the end of the day, we’re bound to Newton’s 3rd law, and if a bullet leaves the barrel carrying 3000ftlbs of energy, then the bolt action rifle will travel in the opposite direction, also carrying 3000ftlbs of energy. The powder that was burned to achieve these two opposite motions was burned while pushing in both directions, so it’s original weight is no longer a part of the equation.

Thankfully, energy doesn’t hurt. Speed does. (A big steel hauler traveling at 1mph has 50 times more energy than a 100mph fast ball, but with one you could hold your hand out and let it slowly impact it while barely feeling it, whereas the fast ball hand is gonna be sore for a week.) A heavy rifle and a light weight rifle will both be carrying 3000ftlbs of energy, but the lighter rifle will recoil FASTER, which is what “hurts” more.
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It's real. All recoil calculators use the powder charge weight in the equation. I am not an expert but if you are then here is the accepted equation:

a firearm, having mass Mf, firing a bullet of mass Mb. The velocity Vf with which the firearm recoils backward is related to the mass of firearm and bullet is given by the equation

Vf=Mb×Vb+Mc×Vc1000MfVf=1000MfMb×Vb+Mc×V where Vb, Vc, and Mc are the velocity of bullet, velocity of powder charge, and mass of powder charge respectively. The velocity of powder charge varies as per the type of propellant used, however, there is a set of averaged values which can be used depending on the firearm:
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What I have not yet seen proven is that case design can give same velocity with 30% less powder, everything else being equal.

I remember reading old gun magazines debating the 308 vs 30-06 controversy. Supposedly the 308 case and powder were more efficient and could match 30-06 performance. We know today that this was total BS, that 308 can not match 30-06 performance, and that those articles were written purely for the purpose of selling gun magazines before we even knew what clickbait was. :)
 
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jethunter said:
I remember back in the 60s and 70s when the gun magazines were debating the 308 vs 30-06. Supposedly the 308 case and powder were more efficient and could match the 30-06 performance. Of course we know today that was total BS. :)
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I thought the claims there were that the "new" .308 could match the "old" -06. Loading them both to max with proper powders that is obviously not true since the -06 has a lot more volume. Either way it's good marketing and poor science.
 
B said:
I thought the claims there were that the "new" .308 could match the "old" -06. Loading them both to max with proper powders that is obviously not true since the -06 has a lot more volume. Either way it's good marketing and poor science.
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It was bad science then, it's still bad science today. And yet here we are. :)
 
Hand Skills said:
Had nothing to do with 'science'.

Factory 30-06 ammo was limited to 60kpsi, and factory .308 was limited to 65kpsi

Hand-loaders are not regulated by SAAMI - some load as hot as their brass will allow 🤷‍♂️
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Of course it's science - it's not magic.

The thread is about getting something for nothing, right? The question asked was if case design of different cartridges allow for a smaller case to match the performance of a larger volume case due to more efficient design. For an example I used the 30-06 vs 308 and it has apparently caused grief for some.

I'm saying The 308 case doesn't match 30-06 performance if you compare them on equal terms. Again, i understand perfectly the SAAMI pressure spec on 308 is higher and so factory 308 ammo is almost as fast as 30-06 factory ammo. I said "when loaded to the same pressure". I don't know how to be more clear.

I'm saying the reason 308 factory can (almost) get 30-06 performance levels is NOT due to "more efficient case design", but because of the difference in pressure ratings.

I'm saying IF you load 30-06 and 308 to the same pressure limit, with the same bullet, with everything else being equal - the 30-06 will out perform the 308, and that is due to the laws of physics - more fuel produces more energy, etc. I don't see what part of this is confusing.
 
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B said:
5k PSI higher max doesnt make a .308 a .30-06. The ability to hold 20% or so more powder is a much bigger benefit.
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Hand Skills said:
More so for those who;

-handload

-shoot bullets over 150gr


Compare factory loaded 150's over a Chrono and hmm, where did the advantage go?
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You are still comparing factory ammo, when you know factory 30-06 and 308 ammo are loaded to different pressure specs.

I've been handloading for 45 years, and using a chronograph for over 30 years. The advantage of 30-06 over 308, both loaded to about the same pressure, is roughly in the range of 200 fps or a bit more.

In factory ammo, the difference is closer to 100 fps advantage for the 30-06 in the stuff I have chrono'd. But velocity varies so much between manufacturers that it's harder to compare apples to apples when comparing factory ammo.
 
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jethunter said:
It is not relevant.
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I think you need to work on your reading comprehension.

Here is the FIRST QUESTION from the ORIGINAL POST

yidava25 said:
Can someone demonstrate a case where, for example, they can push a 180 gr .30 cal bullet at 3000 fps using 80 grains of powder, where another cartridge will duplicate that performance with either more or less powder?
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I provided an example with the .277 Fury in post #8,

The answer is DIFFERENCE IN PRESSURE

That one sailed over your head, so I restated it in post #25

To which you replied, post #26

jethunter said:
Not the same pressure obviously.
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Yes, OBVIOUSLY

Pressure is kinda the KEY ...

jethunter said:
You are still comparing factory ammo, when you know factory 30-06 and 308 ammo are loaded to different pressure specs.
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EXACTLY - that was my point
 
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