Wednesday, June 11, 2008


Ok. This Special AR Upper is on sale at Gunbroker.

I would not recommend anyone purchasing it, even though it's the strongest, lightest one you can find.

See, it's made of Beryllium, the machining and processing of which liberates Beryllium Oxide, which in turn causes chemical pneumonitis and Berylliosis, as well as being very carcinogenic. Frankly, I think it's safer to work with pure cadmium.

I'll be sending an email to that seller shortly.


Anonymous Anonymous said...

Would the upper itself be toxic?

9:29 PM  
Anonymous Mikee said...

Personally, I call shananigans on the upper being made of "60% Beryllium" as the expense, not to mention toxicity, of this casting would be ridiculous. Offering it for sale at $150 makes me think it is something more akin to bronze, a mixture of copper and tin.

Buyer beware....

3:22 PM  
Blogger Sigivald said...

I believe, mikee, that "60%" refers to the finish level of the receiver - ie, 60% of the machining is done.

IIRC, the ATF declares that anything with N hours of machining left is "not a gun" yet, though I more typically see "80%" parts than "60%". In fact, I'd bet that his 60% is a mistake for 80%.

What the "Beryllium" there refers to is uncertain; perhaps just an alloy with a larger than normal but still small percentage?

7:03 PM  
Anonymous TD said...

The gun/not gun distinction is irrelevant in this case, since AR uppers aren't considered guns; the lower is the serialized part of the AR.

9:08 PM  
Anonymous Mikee said...

Thanks for the explanation on the 60%, sigivald....

I read a bit on Be alloys, and the Be is added in the molten stages of the Aluminum alloying process to produce a "better" alloy of Al and Mg, due to the exclusion or gettering of oxygen in the melt. The final concentration of Be in most alloys is very very low, allowing safe machining (say under an air hood) with minimal risk of breathing in beryllium oxide.

That said, more info would be nice to have.

8:59 AM  
Blogger Sigivald said...

td: That is absolutely true, but this person is nonetheless, for reasons I likewise cannot fathom, selling an upper that isn't fully machined.

(Note the lack of ejection slot cover pivot holes, no holes for the takedown pins, etc.)

7:41 PM  
Anonymous Anonymous said...

If that's real the moron should be shot. Beryllium *alloy* is damn tough but the machining processes have to be done under controlled condition. The metal is toxic as is the oxide BTW.

A far superior alloy is silicon bronze. Fabulous machinability, wear resistance, strength, corrosion resistance and beauty.

7:13 AM  
Blogger jon spencer said...

Could it be something like Berylium Copper?
More than a few golf clubs are made out of it.
And a few non sparking tools too.
Of course I keep a little Berylium next to a bottle of this stuff in the garage,

10:40 PM  

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