Understanding cartridge efficiency

bigngreen

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I've built a number of chamberings that are the exact same capacity even using the same brass and the results change based on the design, if the design change effects how the powder burns there is a difference in pressure and timing, wether it's large enough for you to see depends.
Most cartridge comparisons are very biased right out of the gate. It's always a brand new chambering and rifle against a high performing pet rifle and chambering. Very few will be a very direct comparison like using all the same components down to sister barrels.
 

GoosePilot

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To me efficiency is same bullet on least grains of powder or obtaining some level of ft lbs at 1000 yds with best combination of bullet, speed, and powder
 

elkaholic

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I've built a number of chamberings that are the exact same capacity even using the same brass and the results change based on the design, if the design change effects how the powder burns there is a difference in pressure and timing, wether it's large enough for you to see depends.
 

bigngreen

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So I guess the ballistics lab test by Handloader was incorrect ?

Weatherby Kool Aid on sale.
Yep, there is COUNTLESS ways to bias "lab" results!
Would I say it's universal, no but I've seen to many almost exact builds except case design and with pressure equipment on it to buy into the idea that it's only a capacity and pressure equation!
 

degreen

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I've built a number of chamberings that are the exact same capacity even using the same brass and the results change based on the design, if the design change effects how the powder burns there is a difference in pressure and timing, wether it's large enough for you to see depends.
Rich, your design of the SS chamber is what made me wonder about this whole thing. I can't quote anything, but if I remember correctly guys are getting better velocities out of the SS than the SAUM.
 

elkaholic

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Rich, your design of the SS chamber is what made me wonder about this whole thing. I can't quote anything, but if I remember correctly guys are getting better velocities out of the SS than the SAUM.
Thats what many people tell me, but I won't say it because I would be hijacking the thread🙂
Notice, I just quoted "Bigngreen" but what dies he know, right🤔
 

degreen

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I really didn't want to mention names and their designs, but now half the cat is out of the bag. I was also thinking about Ackley's, and other designers. I understand that Ackley's designs do increase case capacity, but not enough to increase the velocity as much as it does. I don't know why, but I think about why the major manufacturers haven't picked up on more of the wildcats.
 

BoomFlop

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degreen

The logistics of it are extremely difficult. Gun manufacturer partnering with a brass company, bullet company, powder company and then all having to take shares of the success or failure. Big risks are involved and millions in advertising and all of that can be killed by poor timing.

On subject, cartridge efficiency to me is speed versus powder needed and amount of recoil. Undersrand that efficiency doesn’t have anything to do with all our performance. High performing products are typically not going to be efficient. Doesn’t matter if we are talking firearms or cars.

Good luck
Steve
 

elkaholic

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If nothing could ever change and be i
I really didn't want to mention names and their designs, but now half the cat is out of the bag. I was also thinking about Ackley's, and other designers. I understand that Ackley's designs do increase case capacity, but not enough to increase the velocity as much as it does. I don't know why, but I think about why the major manufacturers haven't picked up on more of the wildcats.
If technology and innovation never changed anything, we would still be using crank telephones, winning races with Model A Fords, and shooting smooth bore muskets for long range kills!
 

FEENIX

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According to Ramirez and Ramirez (2003), the present invention provides a method of determining the efficiency of a gun cartridge by determining the water weight volume of the cartridge; determining the bore diameter of the gun barrel; determining the weight of the bullet, and calculating the efficiency rating of the cartridge by multiplying the water weight volume by the bore diameter and dividing by the bullet weight. The efficiency rating is optimal between 110 and 145 when the water weight volume is determined in grains, the bore diameter is determined in thousandths of inches and the bullet weight is determined in grains.

In their gun cartridge research study, the inventors from HALO50, Inc, offered the following definitions:

Efficient: Marked by an ability to use the most effective and least wasteful means of accomplishing a purpose or doing a task.

Efficiency: Performance of a task with little or no wasted effort; capability to produce desired results with a minimum expenditure of energy.

Inefficient: Wasteful of energy in performing a task; or underpowered and therefore incapable of performing a task to optimal standards.
 

Lefty7mmstw

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Yep, there is COUNTLESS ways to bias "lab" results!
Would I say it's universal, no but I've seen to many almost exact builds except case design and with pressure equipment on it to buy into the idea that it's only a capacity and pressure equation!
They used 1 barrel for both chamberings... they shot the data in 300h&h first, then lopped enough off the shank to give the 300wsm the same rifled barrel length after chambering and reshot the data as a 300wsm... pretty hard to screw up a cartridge comparo when you are only using one barrel and strain gauge testing to watch pressure... I suppose it can be done, but you would have to be trying to skew results...
 
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