The AR does not use a DI system, though that name has just stuck.
It is an inline piston, the gas that pushes the bullet down to bore is siphoned off and sent down the gas tube, which travels into the carrier key. From the carrier key it travels down into the expansion chamber that is formed by the carrier and bolt tail(behind the gas rings).
When the gas expands it pushes against the bolt tail which has formed a air tight seal thanks to the gas rings, since the bolt cannot move the carrier is instead sent backwards, as the carrier moves rearward the cam pin is engaged and unlocks the bolt.
Once the bolt is fully unlocked the gas inside the expansion chamber is exhausted out of the 2 holes in the side of the carrier and the BCG travels rearward, ejects the brass, and chambers a new round.
If you do not know a DI system is similar in that is has a gas tube, but in a DI system the gas that travels down the gas tube is sent into a small shallow cup in the front of the carrier, when the gas strikes this cup the force is what cycles the action leaving all the gas to be expelled into the action/air.



Reply With Quote

Bookmarks