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What creates a strong cartridge?

 
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  #1  
Old 01-19-2013, 10:33 PM
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What creates a strong cartridge?

Specifically, what allows a cartridge such as the .338 Lapua handle such high pressure? Is it just the thickness of the case web/primer pocket area or the quality/hardness of the brass or both?

Thanks
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Old 01-20-2013, 12:08 AM
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Re: What creates a strong cartridge?

No compromise quality control and damned good engineering.
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Old 01-20-2013, 08:09 AM
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Re: What creates a strong cartridge?

Quote:
Originally Posted by laserflat View Post
Specifically, what allows a cartridge such as the .338 Lapua handle such high pressure? Is it just the thickness of the case web/primer pocket area or the quality/hardness of the brass or both?

Thanks
I believe that it is both, with two independent aspects that create a strong cartridge. First is the inherent design, the second is quality of the of the manufacturing process. The high pressure, magnum cartridges generally are designed with attention to case head thicknes, case expansion dynamics, web, primer pocket etc. The design can be excellent, but if the manufacturing process doesn't meet the design specifications, like dimensional specs, hardness, and the composition of the brass itself, the design benefit is lost. If the manufacturing process is poor, this might not show up at all on the first shot with the cartridge, but certainly will once you begin the reloading process. I have experienced this on several occasions, with well designed cartridges. With their focus on not only cartridge design but also the reloading after market, Lapua does an excellent job with both, as demonstrated with he 338 Lapua.
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Old 01-20-2013, 10:42 AM
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Re: What creates a strong cartridge?

Here is a list of SAAMI pressures for different cartridges

Max Chamber Pressure - SAAMI Specs

Notice the 338 Lapua listed no standard pressure, but I would be surprised if anyone was running a load much over the 65,000 psi standard for modern high pressure calibers like the RUM's and WSM's. IOW the 338 Lapua case should not have to withstand anymore pressure than a 338 RUM, or a 300 WSM or even a 270 Winchester

Pressures are regulated by the amount of powder, burn rate of powder, chamber dimensions, bullet weight and bore size so that it would not matter if you were loading 91 gr of RL22 in a 338 RUM or 69 gr in a 300 WSM you would get the same approximate pressures.

Therefore the pressure on the brass is the same in both

Now if someone can show me where the accepted pressure for the 338 Lapua is more, say 75,000 psi, then I would say that Lapua has a metalurgical secret that they use in the their "super brass"
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Old 01-21-2013, 08:42 AM
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Re: What creates a strong cartridge?

got to agree. Weatherby been loading to that level for years and there brass is nothing special. Id say its a combination of the fact that guns are made with better steal quality then they were many years ago and liability has scared the ammo manufactures into neutering most of there ammo so a guy thinks it takes something real special to do what was done 40 years ago with guns that werent as good as there selling right now. Most of the guns out there chambered for it are quality factory guns or customs that are built no expense spared so im sure there not so gunshy about publishing loads up to its true potential. Not much chance someones going to chamber an old 93 mauser in a round like that!
Quote:
Originally Posted by woods View Post
Here is a list of SAAMI pressures for different cartridges

Max Chamber Pressure - SAAMI Specs

Notice the 338 Lapua listed no standard pressure, but I would be surprised if anyone was running a load much over the 65,000 psi standard for modern high pressure calibers like the RUM's and WSM's. IOW the 338 Lapua case should not have to withstand anymore pressure than a 338 RUM, or a 300 WSM or even a 270 Winchester

Pressures are regulated by the amount of powder, burn rate of powder, chamber dimensions, bullet weight and bore size so that it would not matter if you were loading 91 gr of RL22 in a 338 RUM or 69 gr in a 300 WSM you would get the same approximate pressures.

Therefore the pressure on the brass is the same in both

Now if someone can show me where the accepted pressure for the 338 Lapua is more, say 75,000 psi, then I would say that Lapua has a metalurgical secret that they use in the their "super brass"
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  #6  
Old 01-23-2013, 04:14 PM
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Re: What creates a strong cartridge?

Im not saying its anything magical. But I didnt think it was a secret that .338 Lapua brass, and all Lapua brass for that matter, holds up under many repeated full-tilt loads better than most other brass..

Thanks for the replies yall, anyway, I was wondering if you took, say, the .50 BMG, which is fairly low pressure compared to modern magnum rounds, and doubled the thickness of the brass throughout most of the case, and had very high quality brass used, would it make very much difference in how much pressure it could handle? Assuming you have an action that can handle it of course.. Or does the case head size dictate that theres going to be so much bolt thrust, that case thickness doesnt matter much at that point?

Thanks again
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  #7  
Old 01-23-2013, 04:49 PM
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Re: What creates a strong cartridge?

The production process, especially the right mix of case hardening via forming and anealing gives a case the right properties.
The less steps you take, the less the cost, but also the less ductile the case will usually be.
Thickness and brass' (educt) quality are of course important too.
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