There are two rounds being manufactured. One is the 277 Fury, which is a 6.8x51mm. The other is the 6.8x43mm. The Fury is too large for the M16/AR 15.
Just at a glance you can see the .277 Sig Fury is a really unique round. First thing you'll notice is that it has a bi-metal casing which has a steel metal base and brass body. The metric dimension of the Fury is 6.8x51mm, which is a big boy. Standard .277
Fury ammo holds 140 grains. This means its over twice as powerful as the standard 62 grain 5.56 NATO round. This high power round has a chamber pressure of 80,000 PSI, which is practically unheard of for any military ammunition. For comparison, the 5.56 NATO goes out at about 62k PSI and the 7.62x51 NATO is at 60.2k PSI. Having 18-20k more PSI coming out of a barrel is a ridiculously huge advancement in stopping power. This means the .277 Fury has a Muzzle Velocity of 3,000 FPS put of a 16in barrel. Essentially this round is just a magnum version of a 6.5 Creedmoor on steroids.
While the 6.8 SPC is currently widely available, it is not the same as the 277 Fury. The 6.8 SPC (or 6.8x43mm) was made for the AR-15 platform. 277 Fury is too large to fit into any standard AR-15 platform. While these rounds have a lot in common, the .277 is an absolute monster. Here is a chart comparing the 277 Fury to the 5.56, 300 Winchester, 308 Winchester, and the 6.5 Creedmoor.
Today at M*CARBO we examine the newly developed Sig .277 Fury caliber round designed to replace the 5.56 NATO round the Army currently uses. We have a full break down as well as ballistic charts to keep you up to date on the latest firearm news.
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