you buy a scuba tank with an adaptor to refill your own tank and then obviously take to a dive shop when you need to refill
For the marui you'd be better off getting a ghk m4 they must have the worst gas efficiency in a gbb m4 - Good read below btw
That's a bit disappointing, oh well. Thanks the heads up though mate Never thought of using an actual dive tank as opposed to a specific airsoft / paintball one if that's what you're suggesting b1ng.
I think what he means is you can buy a scuba tank to refill your normal tank then when the scuba tank runs out refill it and start again