Simo GBB shows the converted HK416 GBB to be CO2 powered and can take in a drum magazine... "Hello, this is Simo. After a long hiatus, we’ve brought back the HK416D that we created. I had previously converted it to use CO2, but after that, the bullets stopped coming out. Either the semi-automatic function would stop working, or there would be issues with the valve. I encountered various problems and couldn’t fire it, so I left it alone for a year.

About a week ago, I started tinkering with it again and shot a video. Shooting with CO2 was enjoyable for a while. However, two days before I was due to shoot it, it reverted to its previous state. In the end, I decided to participate on the day of the shoot using freon.

Since I had brought it with me, I played with it with a drum magazine. Do check out the power shooting. Apart from the recoil, drum magazine is overwhelmingly superior. It operates smoothly due to the large amount of gas. The only downside is that I can’t enjoy changing magazines."