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What happened to the AR-10 Ultra Magnum?

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What happened to the AR-10 Ultra Magnum? was created by silver78

ArmaLite’s AR-10(T) Ultra in .300 Remington Short Action Ultra Mag. (RSAUM). Pushes out 180 grainers @ 3,000 fps.

Seems to be discontinued? Nothing on Armalite's website. Here is an article that describes it.

www.americanrifleman.org/ArticlePage.aspx?id=1599&cid=4
12 years 2 months ago #10307

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Replied by AR260rem on topic Re: What happened to the AR-10 Ultra Magnum?

It was discontinued, I was looking for one too. There was one on Gunbroker for sale about 2 months ago, looked new and the price was reasonable. You can still find them on there from time to time. I read there were some feeding problems, not sure if that was true or not. Seemed like a logical step up in power though for the AR-10, not sure why it was discontinued.
12 years 2 months ago #10486

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Replied by 13fcolt on topic Re: What happened to the AR-10 Ultra Magnum?

It's got to do with the interest in the short magnums going limp. I still love them, but overall they seem to have been written off and I can't understand why. I know I took a beating when I sold my FNA5 spr .300wsm. The reason being it wasn't .308 or the longer .300wm. Had the rifle been in either of those It would have sold for asking price almost immediately.
ArmaLite Super SASS for sale W/ extras. PM for details.
12 years 2 months ago #10497

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Replied by AR260rem on topic Re: What happened to the AR-10 Ultra Magnum?

That makes sense, especially the 300 RSAUM. Seems like the Winchester version caught on some in bolt rifles but the Remington version is dead. I read the TSB stating the winchester version was totally unsuitable in AR platforms due to case construction. That's too bad though, seemed like a nice step up in power for the AR-10 platform. I see the 338 federal is now the big caliber for the AR-10, but the trajectory limits the range some, and 250 gr bullets can't be used. Its not a 338-06 or 338 Win Mag. Might go the same way in the end. Though a carbine 338 Federal might make me open my wallet :)
12 years 2 months ago #10505

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Replied by foxhunter on topic Re: What happened to the AR-10 Ultra Magnum?


Amen to that.
12 years 2 months ago #10510

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Replied by AR260rem on topic Re: What happened to the AR-10 Ultra Magnum?


I thought I read somewhere that Armalite was working on one that should be out this year. They were supposedly working on getting the gas system to work correctly with the carbine version. Don't know the validity of that though.

Glad I'm not the only one :)
12 years 2 months ago #10515

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Replied by SOC on topic Re: What happened to the AR-10 Ultra Magnum?

You could have a 308 barrel re-chambered, the bolt opened up, the ejection port widened and some work done to the extractor and convert to 300 RSAUM. (probably easier to buy used, I've never seen one with much of a round count)

I'm tinkering with a 408 cheytac shortened to 308 length, necked down to 338 and the rim rebated to 308 size. The idea is to turn the AR-10 mag into a single stack sort of like what the 50 Beowulf does in the AR-15.

Sort of a 338 Super Short Mag, powder capacity looks to be really close to the 338 Lapua but I plan to test it using the short mag powder RL17.

The question is, if it leaves me enough barrel wall to contain 65,000 PSI, if so I'll have 338 Lapua ballistics from ANY AR-10 with just an upper swap.

If it cant take the pressure I'll shift the project to a .510 caliber sub sonic/low supersonic velocity round.
The following user(s) said Thank You: jtallen83, Libertarian623
10 years 3 months ago #34179

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Replied by Siscowet on topic Re: What happened to the AR-10 Ultra Magnum?

When you get done with that project you should have your own Guns and Ammo write up. Ditch the lava lamp for the photo spread though.
10 years 3 months ago #34180

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Replied by OleCowboy on topic Re: What happened to the AR-10 Ultra Magnum?


I am looking forward to more reporting on this :twothumbs:
10 years 3 months ago #34189

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Replied by SOC on topic Re: What happened to the AR-10 Ultra Magnum?

If I got a photo spread it would all be about the rounds and the rifle.
10 years 3 months ago #34232

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