[BioRage]

1) GBBR Primary
2) AEG or another GBBR Primary. (If you run a WE system then this would be simple)

Usually when you gas up you should be good to go, depends on how many mags you carry into battle with you. I typically would carry 6-7 on me, with the one in my gun already. Even when going back tot he staging area, I would just top off the gas for the "Just in case factor" even though mags are supposed to last 2-3 re-fills.

I never carried any gas with me onto the field, because I only used GBBR in CQB and skirmishes that didn't exceed 60 minutes. Sometimes you could be shooting with one mag, and it could vent all the gas out, I would just toss that back into the pouch and proceed with the next mag.

I never liked to carry more then I needed, however I think investing in the AI Gas canister would be an ideal investment for any GBB user.

I'm sure you know to never use full auto on the GBB, since your shots are limited to a maximum of 40.

Never experienced a MilSim with a GBBR, but I assume you'd carry a gas canister with a speed loader to refill your mags when you can, that would make the most sense.

Make sure you keep your gun and magazines clean after each use, this would ensure you don't have bad luck if your mags were to leak. If they had a slow leak I would use those mags first during the beginning of the rounds first.

Edit:

You could also build a spare bolt too as a back up, if you didn't want to invest into a new GBB.