Double shoulder angle?

Bwana John · May 8, 2022

What would be the purpose of this?

" A double shoulder angle firearm cartridge for AR-15, bolt action rifles, pistols, and any other firearm includes a firearm cartridge comprising a case that holds a primer, powder, and bullet. The case is defined by a case head forming a rim and an extractor groove, a body section extending from the case head, at least two shoulder angles extending from the body section, and a neck section extending from the shoulder angles. The shoulder is defined by at least two angles tapering into each other in an integral configuration. The first angle is 30°; and the second angle being a 17° 30? shoulder angle, substantially the same as the 7.62×39 Russian round. The diameter of the case is approximately 0.447 inches. The length of the case is approximately 1.530 inches."

Bwana John · May 8, 2022

I found more information, it appears that he is trying to introduce a new cartridge and chamber that has more velocity than the parent cartridge, that can still chamber and discharge the parent cartridge.

https://patentsgazette.uspto.gov/week28/OG/html/1488-2/US11060828-20210713.html

AJC1 · May 8, 2022

Any of the Ackley cartridges do the same thing.

Bwana John · May 8, 2022

AJC1 said:
Any of the Ackley cartridges do the same thing.

That was my thought also.
Can a AI cartridge be chambered in a semiautomatic and still operate the rifles mechanism when using the original non-AI ammunition?

AJC1 · May 8, 2022

Bwana John said:
A

That was my thought also.
Can a AI cartridge be chambered in a semiautomatic and still operate the rifles mechanism when using the original non-AI amunition?

Any standard cartridge can be loaded and fired in ai but will not function in a Sammi chamber

Bwana John · May 8, 2022

Let me try this again, I was not very clear.

Can a semiautomatic or select fire rifle be chambered for a Ackley Improved cartridge function correctly when using the parent cartridges non Ackley ammunition, not just discharge the non Ackley chambered cartridge, but fire/extract/eject/reload/lock into battery/do it again?

Bcwitt · May 8, 2022

Some Ackleys have reduced body taper in addition to blown out shoulder. It might cause a problem w a large magazine.

Varminterror · May 8, 2022

Bwana John said:
Can a AI cartridge be chambered in a semiautomatic and still operate the rifles mechanism when using the original non-AI ammunition?

Largely depends on how critically balanced is the gas operating system - but in general, yes.

I have had AR’s and LFAR’s in 223ai, 243ai, and 7-08ai. I opened my gas block a half turn to operate the actions on factory/non-AI ammo.

jmorris · May 9, 2022

Bwana John said:
Can a semiautomatic or select fire rifle be chambered for a Ackley Improved cartridge function correctly when using the parent cartridges non Ackley ammunition, not just discharge the non Ackley chambered cartridge, but fire/extract/eject/reload/lock into battery/do it again?

@Hoser could likely answer your question, IIRC he is fond of the .223 Ackley.

Hoser · May 12, 2022

I have a couple 223 Ackleys in semi auto and bolt action rifles.

I do all the fireforming in semi autos using regular old 223 ammo loaded to normal specs. For me normal is about an 8 on a 1-10 scale with 10 being max.

AJC1 · May 12, 2022

Hoser said:
I have a couple 223 Ackleys in semi auto and bolt action rifles.

I do all the fireforming in semi autos using regular old 223 ammo loaded to normal specs. For me normal is about an 8 on a 1-10 scale with 10 being max.

Interesting. I figured you would get more case stretch in a semi...

JFrank · May 12, 2022

Bwana John said:
Let me try this again, I was not very clear.

Can a semiautomatic or select fire rifle be chambered for a Ackley Improved cartridge function correctly when using the parent cartridges non Ackley ammunition, not just discharge the non Ackley chambered cartridge, but fire/extract/eject/reload/lock into battery/do it again?

After the first firing it’s an Ackley’ why resize to the parent case ? Seems like that would put the shoulder under a lot of stress perhaps destroying the newly formed case..

taliv · May 12, 2022

The real AI cartridges have a .004” difference in headspace to “crush fit” the parent cartridge in the AI chamber so that it is properly aligned before fire forming. Ie on a bolt gun it is noticably harder to close the bolt on the parent cartridge.

I’m not saying you can’t chamber a full auto in AI and have it function with the parent cartridge. However, I wouldn’t recommend it for regular hard use as it’s almost definitely going to be less reliable.

Varminterror · May 12, 2022

AJC1 said:
I figured you would get more case stretch in a semi...

Really only if your “gas and mass” are out of balance.

But in fairness, most ARE because we generally accept that reliability trumps brass life when we’re shooting gassers.

Double shoulder angle?

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