Type: CO2 Blowback Machine gun. Manufacturer: Cybergun - KWC. Model: Mini UZU. Materials: Metal and Polymer. Weight: 4.8 pounds. Barrel: Metal, non-rifled. Propulsion: CO2 x1. Action: BB Semi auto only - Airsoft selectable semi & full auto, single action only. Ammunition Type: 4.5mm Steel BB - 6mm Plastic Airsoft Ammunition Capacity: 25 - 38 rounds FPS: 350 - 400 In terms of build quality they are made almost exactly the same and weigh in at a hefty near 5 pounds, the only differences are the inner barrel and magazines to accommodate the different sized ammo. The BB version has a 25 round single stack magazine that does not have a follower to stop the bolt from continuing to operate even after the magazine is empty. While the 6mm Airsoft version has a double stack magazine that holds 38 rounds and does have a follower to stop the bolt which can save you some unintentional wasted CO2. Read full article here: https://www.replicaairguns.com/2013/4/19/kwc-mini-uzi-bb-versus-airsoft-comparison-review.html Buy BB Mini UZI in Canada: https://www.replicaairguns.ca/kwc-mini-uzi-bb-machine-gun Buy BB Mini UZI in the US: https://www.replicaairguns.us/kwc-mini-uzi-bb-machine-gun Buy Airsoft Mini UZI in Canada: https://www.replicaairguns.ca/kwc-mini-uzi-blowback-6mm-co2-airsoft-gun Buy Airsoft Pistols in the US: https://www.replicaairguns.us/kwc-mini-uzi-blowback-6mm-co2-airsoft-gun