Below are the sub-systems of the AR-15 carbine/pistol/rifle. These diagrams are for the standard handguard versions, free float handguards will be slightly different.
![Lower Receiver Diagram](http://franklinordnance.com/wp-content/uploads/2019/12/lower-copy.png)
![Buffer Diagram](http://franklinordnance.com/wp-content/uploads/2019/12/buffer-copy.png)
![Upper Receiver Diagram](http://franklinordnance.com/wp-content/uploads/2019/12/upper-copy-1024x776.png)
![Bolt Carrier Diagram](http://franklinordnance.com/wp-content/uploads/2019/12/bolt-copy.png)
![Barrel Assembly](http://franklinordnance.com/wp-content/uploads/2019/12/barrel-copy.png)
Below are the sub-systems of the AR-15 carbine/pistol/rifle. These diagrams are for the standard handguard versions, free float handguards will be slightly different.