cartridge efficiency?

B

BryanWang

Guest
how do you measure cartridge efficiency? or how do you tell if one cartridge is more efficient than another just by looking at the diagram of the cartridge. I know fatter ones are better than old skinny ones. but how fat? if it's fat like 243 wssm, is it still efficient? does it has anything to do with bore/case volume ratio?
any input would be appreciated!
 
I'm not sure how you could tell by looking at the case whether or not it's efficient.

The relatively long and skinny .223 Rem is more efficient than the short and fat .22 WSSM, and the .222 Rem is more efficient than either of them. The 6 PPC is more efficient than the .243 WSSM by a LONG shot, and more accurate too. The only way I know of to tell how efficient a cartridge might be is to determine velocity per grain of powder burned. A small case no matter what its shape will nearly always be more efficient than a large case no matter what its shape is.
 
I think that the smaller the case volume, for a given bore diameter, generally, the more efficient, effency defined as velocity per powder weiight, at a given bullet weight. Another variable that can enter into the problem is how much pressure a case is rated for.
 
Pal, it's achieved velocity per grain of powder with direct relationship between the case volume capacity, loading density/pressure and the size of the bore. Rad
 
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For each cal, peak efficiency would amount to completely burning all powder nearest or inside the chamber, AND producing reasonable peak pressure AND lowest muzzle pressure with adequate velocity and minimal recoil.
With this criteria, smaller cartridges for bore, with medium weight bullets, and good powders, usually 'seem' to perform very 'efficiently'.

But nothing is free, and efficiency OVERALL will include your entire shooting system -vs- application.
For example, if you need highest BC bullets cooking 1Kyd downrange before blown all over the place, a 6PPC will 'seem' less efficient in a hurry. In this application, a 6br or 243win variant, combined with the right powder, will likely 'seem' more efficient.

Ultimately, it's all tied to the chosen bullet. Then, the right powder with the right capacity to produce highest efficiency while meeting your needs.
SIMPLE:rolleyes:
This is where QuickLoad shines..
 
Get Ackley's........

books & read them; They can be a bit confusing until you get some more experience w/different cartridges, so don't just throw them away in frustration, & always regard the receipes w/a large grain of salt, because many of those loads were concocted before handloaders had all the resources they have today. Probably, well most, everyone on the CF boards has read those books a time or two, for various reasons.
 
BryanWang said:
how do you measure cartridge efficiency? or how do you tell if one cartridge is more efficient than another just by looking at the diagram of the cartridge. I know fatter ones are better than old skinny ones. but how fat? if it's fat like 243 wssm, is it still efficient? does it has anything to do with bore/case volume ratio?
any input would be appreciated!
Click to expand...


15foroo.jpg
 
JerrySharrett said:
Great chart Don. Did you make it?
Click to expand...

Hi Jerry, no I didnt make it, but I had it stored in a PC BR folder as a picture URL, without a source reference............I think I copied it off a past forum posting from the 6br website.............Don

PS.....most interesting to me was that the .50 BMG cartridge was listed as the least efficient and most overbore. I would think that this military cartridge, one of the military cartridges with the greatest longevity of useage, would never be considered as overbore, and would have a reputation for good long barrel life, maybe not.

PS2.......just did a google search and found a source for the "overbore" chart;

http://accurateshooter.wordpress.com/2008/05/05/overbore-cartridges-a-working-definition/
 
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So What's The Big Deal.

If efficiency is simply a measure of how what can get the most by using the least, then it would be a pretty dull world.

After all, my Saturn Vue that I tow behind my Motorhome is probably a lot more "efficient" than, say, Jimmy Johnsons Sprint NACAR Racer, but nobody is paying millions of dollars to watch me drive a Saturn.

The 6PPC, and many of the other small 'efficient" cartridges, will literally stack one bullet on top of another. It's phenominol accuracy potential is a direct result of it's efficiency.

But, if I am staring out over 500 yards at an Elk, and he has presented a great quartering shot, I don't want that super "efficient" 6PPC, I want something that is so darned "inefficient" that it will push a 190 grn bullet far enough to drop that Elk in one shot.

You are not going to do that with 30 grns of powder.

The 50 BMG listed as one of the least effiecient rounds ever??. Ask the millions of enemy combatents, on the ground, in the air, and on the sea, about that.......jackie
 
More Efficiency Equals More Consistency

Below is the " hands-on experience/ testimony by another forum contributor. My personal experience with a shortened 6.5 WSM case and recently a shortened (.300) 30 cal shortened Lazzaroni Patriot/project was similar. Others I have talked to that have personally checked it out, verified the same type of results, all reported very good accuracy. To me, its like the short stroke engine being an improvement over the previous longer stroke design. It seems like its because of more complete combustion, and therefore more consistent shot-to-shot combustion. This might not indicate anything, or mean anything to some, but it does to me. I think "the hand is writing on the wall". Larry Kramer, Victoria, Tx.



BillK

Charter Member
Registered: 01/10/07
Posts: 83
10/30/07 #8

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I own both a 6.5-284 and a 6.5-243wssm. I have shot the 6.5-284 longer but I like the 6.5wssm better. Both guns shoot the same 140gr bergers at 3070fps. My 6.5-284 uses 53.4gr of re22 to do this. My 6.5wssm uses 48.8gr of re22 to do the same velocity.
 
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