Tokyo Marui KSG Gas Shotgun: First Impressions in Rifles (Gas) Posted September 23, 2016 · Report reply I hope it holds up with the propane/green gas. I've had to resort to duster for my current one. A lot of the 870s I've owned eventually had a leak from the body or an expanded gas that after prolonged use. Breacher had a leak from the body that needed maintaining, not sure if it was entirely caused by propane use though, could be an overall maintenance issue. Hopefully this holds up. A TM gas shotgun on the higher pressured gas is just mean for CQB, it's so fun I love it.