What would be a benefit of expanding the gas port and tube coming out from the gas block? Is there any benefit other than what I could see as more pressure coming back into the carrier group?
The gas pressure will be regulated at the gas port, so it’s not going to give you any more gas, or more pressure.
By having a higher volume in the gas tube, it takes longer for the gas to pressurize that space, and longer for the gas pressure to rise inside the bolt carrier, delaying operation.
…at least that’s my take on it.
More pressure getting into the carrier is not a benefit, its called over-gassing and it causes problems. There is a theoretical benefit to a gas tube with a larger volume when used with an already over-gassed gun for the reason mentioned by eod.
Discussion of Fatboy gas tubes