Sig 300 BLK

[wvcardsfan]

I found a round bearing this mark while sorting some range brass and had never heard of such a caliber, so I looked it up. I'm seeing info on rounds of this caliber with 220 grain bullets. Since this casing is 1 3/8" in length, that seems like a lot of lead. The diameter certainly doesn't look like any .30 caliber I can remember seeing. This is a tiny piece of brass. Can anyone educate me some on this?

 

[mcb]

The Sig is simply the manufacture. The cartridge's official name is 300 AAC Blackout.

Rather than ramble and type a lot I would point you to the Wiki article on the cartridge: https://en.wikipedia.org/wiki/.300_AAC_Blackout

It is a very popular cartridge due to the fact that with a simple barrel change it can be run in a standard AR. 300 AAC Blackout cases can even be formed from 5.56/223 cases with minimal effort. It suppresses very well while at the same time still having fairly good supersonic performance with properly selected ammunition.