Originally Posted by BoltsFan
Why does it say (auto) I noticed they have a (semi) on their website.
Does it have all components in it or do I still need to buy firing pin extracted etc?
The auto is an M-16 bolt carrier while the semi is the AR-15. The auto is preferred in the carbine variants do to the faster cyclic rate of the carbine gas system (the auto carrier is heavier). The higher pressure= faster cyclic which is harder on the bolt and may reduce reliability. The faster unlock time in the bolt causes increased centrifugal force on the extractor which could cause the extractor to slip off the case rim.
Several things can be done to avoid this. A stronger extractor spring, auto carrier to increase the mass that is moved which will slow down the cyclic speed and heavier buffers.
No (before you ask) it is not illegal to install an auto carrier in a semi auto rifle.
BTW: the bolt is exactly the same, the carrier is different.
Hope this helps!