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Understanding cartridge efficiency

So if a 300 wm can push a 180 at same speed as 30 nosler using 4 gn less powder I would say yes that makes a 300 wm more efficient then a 30nosler, how about comparing a 7SS to a 7Saum should be very close case capacity

OMG, did you NOT see I said they are NOT the same capacity.

OK, that is much better, but they do not have the same case capacity (.30 Nosler has the edge, it also varies from brass manufacturer).
The efficiency between the two is purely relative to the end-user.
 
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The efficiency or optimal case design is tagged by everybody that comes up with a new cartridge, then they go on to explain their reasoning and we go and buy the latest and greatest.
 
What is wrong with the proof barrels? Why are they building pressure in spikes. How is Proof the number 1 barrel used in PRS if there are so many issues?
Shep
They are having MANY issues with tight spots which cause pressure spikes early and low velocity. Ive had at least 10 clients not counting suspected ones. Ive talked to several smiths lately who have experienced the same thing.
Things happen, and I feel badly for Proof and hope they get it figured out.
 
Wouldn't they catch tight spots when air guaging the barrels for qc? I use mostly Bartlein and Kreiger on customers guns. I didn't know proof was having issues. How do you know you got a bad one?
Shep
 
Wouldn't they catch tight spots when air guaging the barrels for qc? I use mostly Bartlein and Kreiger on customers guns. I didn't know proof was having issues. How do you know you got a bad one?
Shep
If your velocity is down and/or pressure is occuring way lower than normal charge weights, you probably do. Everyone that I know of that was checked by Proof, indeed had a problem.
Ive decided for now to drop them entirely because of customer after customer having issues.
 
This thread is like the energizer bunny, it keeps going and going and going and going and going.

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My bet is 15 pages, at least
 
Here we go again. There is NO published safe load that allows a 300 WSM to push a 180 as fast as a 30 Nosler. Less capacity ALWAYS equals less velocity.

"There is no substitute for cubic inches."
 
Hi a close example would be a 243 Win and 243WSSM.
I have loaded both with the same projectile and same charge of H4350 and in 24" barrels they had the same velocity.

The difference in factory ammo is the pressure that they are loaded to.
Also the difference although minor is basically 1/2" of barrel length.
As the WSSM case is fairly close in capacity it is shorter so having a 24" barrel on both the WSSM essentially has more combustion.area if you me a sure from the front of the chamber to the muzzle.

Some cartriges are more efficient take a 6mm Dasher it will get close to a 243 however that is due to the pressure.
And the last thing is to gain 200fps over 3000fps takes x powder increase but to gain another 200fps might take 3 or 4 times x in slower powder.
 
If a person was to take two cartridges that have the same case capacity, but one is considered more efficient than the other. What are the pro's of the more efficient case?


Probably using less powder in one to obtain the same velocity within allowable pressures. Of course if the load doesn't "shoot" it's sorta moot.

Take something like a 284 Win case and shorten it by half and increase the diameter so that the volumes are equal to the base of the neck. The .284 S & F [Short & Fat] could turn out to be a more efficient design, but not worth the bother from a production standpoint or even a wildcat/gunsmithing standpoint.

P O Ackley demonstrated with the 6.5-06 to 6.5-06AI that maximum efficiency was reached at the 6.5-06 point, but lots of folks [me included] like the AI version. I don't know if anyone after him bumped the AI shoulder back until case capacity equaled that of the base 6.5-06 and then did a comparison. If the 6.5-06AIS Ackley Improved Short turned out to be more efficient the best pro that could result would be if someone would commercialize it. If not, the wildcatters and free spirits would probably enjoy its benefit/s just because they could.
 
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