The following excerpt is from an article that originally appeared on The Firearm Blog
Brownells now makes lightweight AR-15 bolt carrier groups. While the bolt itself is a standard one, the bolt carrier has been lightened by cutting and machining out the material and leaving just enough to make it functional. As a result, the new BCG weighs 8.2 ounces.
The new Brownells lightweight bolt carrier is machined out of 8620 tool steel. The bolt is made of 9310 steel and is also magnetic particle inspected (MPI). The M16 notch is still retained on these bolt carriers in case if you have a lower receiver with a fun switch. The forward assist notches are also retained.
This BCG is advertised to reduce the felt recoil. It may also be a useful part for lightweight AR builds. According to Brownells, the new BCG is compatible with 5.56x45mm NATO/.223 Remington, .300 Blackout and .204 Ruger calibers.post was originally published on this site