What folks don't seem to get is as long as the proper amount of gas gets to the bcg and you have the recoil system to handle the mass moving it DOESN'T MATTER how long your barrel and gas system is. It's all about balancing the amount of reciprocating weight. Dwell time does factor in to the equation. As long as the bullet stays in the barrel long enough for the proper amount of gas to move the bcg there is not a dwell time problem.