As opposed to a 22 conversion, for a few more bucks get a dedicated upper and not reset your sights when you want to switch back to 5.56. The 1:16 barrel is really made for 22's. DOES NOT INCLUDE DOT SIGHT. Dot sight available for $125 Here's a review: ATI Chiappa M4 .22LR Upper Review American Tactical / Chiappa firearms M4-22 .22LR upper receiver for AR-15 rifles. Mounts on any standard AR-15 lower receiver. Specifications and Features: Caliber: .22 LR Barrel length: 16.125 28 round magazine Includes bolt carrier group and charging handle M4 Profile Barrel Low profile dummy gasblock M4 plastic handguards Flat top reciever Matte black Polymer Upper Receiver Like new condition - $250 with 1 factory magazine, and one black dog 26 round mag. (shorty black dog 10 round in photo not included) and manual. This upper is for sale as the complete rifle in the rifle section also - which ever way it goes first then it's gone.