Rebated rim cartridges... Clever stuff

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Rebated rim cartridges... Clever stuff

Post by buster » 06 Nov 2014, 4:41 pm

Just doing some reading on cases and found this pic of rebated case rims. Jumping to conclusions I know, but first thought was that it just looked fiddly and could be annoying to pinch at the little rims if you needed to get one out.

rebated_rim-cartridge.png
The .50 GI (left) with rebated rim, compared to the rimless .45 ACP (right)
rebated_rim-cartridge.png (81.41 KiB) Viewed 5843 times


Clever reason though... They get a lot more out of a gun with less parts by keeping the rim smaller when upping the rest. Clever chaps these gun designers.

Rebated rim

Rebated rim cartridges have a rim that is significantly smaller in diameter than the base of the case, serving only for extraction. Functionally the same as a rimless case, the rebated rim provides some additional benefits when considered in conjunction with other cartridges.

One example of a rebated rim cartridge is the .50 Action Express (or .50 AE), commonly chambered in the Desert Eagle pistol. In order to simplify production, and to decrease the cost of ownership, the .50 AE was designed with a rebated rim which matched the diameter of the rim of the .44 Magnum, which was the most common caliber used in the Desert Eagle. By using the same rim dimensions as the .44 Magnum, a Desert Eagle could be converted from .44 Magnum to .50 AE by merely changing the barrel and magazine.

Other convertible cartridges, such as the short-lived .41 Action Express (with the same rim diameter as 9×19mm Parabellum) used in the Jericho 941 convertible pistol, would function in the same magazine, and thus required only a barrel change to change caliber. The recent (early 2000s) Winchester Short Magnum, Winchester Super Short Magnum, and Remington Ultra Magnum and Remington Short Action Ultra Magnum families of rifle cartridges also feature rebated rims. In these cases, the rim was designed to fit bolt faces for existing magnum rifles, but the case was made wider to allow a greater powder capacity.

The .50 Beowulf also uses a rebated rim design. This round is used in specialized AR-15 upper receivers, and the rim matches the size of the rim of the 7.62x39mm, allowing those parts to be used in the custom-built upper receivers.


Interesting I thought so there is a share :)
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Re: Rebated rim cartridges... Clever stuff

Post by MeccaOz » 06 Nov 2014, 5:15 pm

Now it makes sense :D
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Re: Rebated rim cartridges... Clever stuff

Post by Chronos » 06 Nov 2014, 5:30 pm

I don't get it, The interest I mean. I guess in a pistol it may be a new idea.

My .284W has a rebated rim. It's pretty much a magnum diameter case but fits a. .308 sized bolt face.

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Re: Rebated rim cartridges... Clever stuff

Post by buster » 07 Nov 2014, 9:18 am

Well I was talking about pistols, not rifles.

In your rifle the projectile is always smaller than the case diameter, so if you wanted to go up from your .284 to .308 you just change the barrel.

Going up to .50 AE from .44 mag everything gets bigger, if they hadn't done the rebated rim you'd need another pistol instead of being able to just swap the barrel on your DE. Like it says, decrease the cost of ownership.

Anyway, I thought it was interesting. Maybe I'm more easily impressed.
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Re: Rebated rim cartridges... Clever stuff

Post by whert » 10 Nov 2014, 1:40 pm

It would be more interesting if I lived in the US and could actually get the pistols without going through a year of licensing crap here :lol:
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Re: Rebated rim cartridges... Clever stuff

Post by joojoobeans » 11 Nov 2014, 2:59 pm

As long as it puts the bullet through the red dot that's as clever as I need it to be

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