The port pressures are in thousands of pounds..A few ounces more in buffer weight is not going to have much effect on lock time..
For example, the original port pressure using the original IMR 4475 powder was 14,400 PSI.. When they switched to WC846 ball powder, the port pressure increased to 15,400 PSI..This is the force that unlocks the bolt..The actual dwell time is the point between the gas port and the end of the barrel when the gas system is charged..All things being equal (gas port /size/port location, remaining the same) the residual pressure was much higher with the ball powder than the original IMR powder, hence the carrier velocity increase and cycle rate problems..
Lock time is effected by the cam track design and port pressure..Once the bolt unlocks, the residual pressure is vented out the ejection port..The higher the port pressure, the higher the residual pressure.. Once the bolt unlocks, the carrier velocity is affected by the residual pressure and carrier weight does become a factor..
As Colt learned in the 1960's and the SilencerCo high speed video graphs revealed, the buffer weights effect on lock time was insignificant, even suppressed.. Residual pressure / carrier velocity is effected by buffer weight..
When LMT designed their enhanced bolt carrier for shorter barreled gas systems, they changed the bolt cam track to increase the lock time so residual pressures would have more time to dissipate after the bullet left the barrel... It worked very well.. The reason the military rejected the enhanced bolt carrier for shorter barreled rifles was because it was not reliable with rifle length gas systems (too low of residual pressure to reliably cycle the rifle length gas system) and they didn't want to have two types of carriers in the supply system..
When the bolt unlocks, the extractor lifts completely off the case rim and is dependent on the same residual pressure to hold the case against the face of the bolt until the extractor lowers back down to allow extraction....
A good example of residual pressure would be an air hose..When an air hose is plugged into a compressor, the air hose is charged..When you unhook the air hose, the air escaping from the hose is residual pressure..
Balancing the residual pressure is what determines a reliable gas system and there are different ways to approach this..Which one is optimum is what creates a great many debates on gun forums..
For example, the original port pressure using the original IMR 4475 powder was 14,400 PSI.. When they switched to WC846 ball powder, the port pressure increased to 15,400 PSI..This is the force that unlocks the bolt..The actual dwell time is the point between the gas port and the end of the barrel when the gas system is charged..All things being equal (gas port /size/port location, remaining the same) the residual pressure was much higher with the ball powder than the original IMR powder, hence the carrier velocity increase and cycle rate problems..
Lock time is effected by the cam track design and port pressure..Once the bolt unlocks, the residual pressure is vented out the ejection port..The higher the port pressure, the higher the residual pressure.. Once the bolt unlocks, the carrier velocity is affected by the residual pressure and carrier weight does become a factor..
As Colt learned in the 1960's and the SilencerCo high speed video graphs revealed, the buffer weights effect on lock time was insignificant, even suppressed.. Residual pressure / carrier velocity is effected by buffer weight..
When LMT designed their enhanced bolt carrier for shorter barreled gas systems, they changed the bolt cam track to increase the lock time so residual pressures would have more time to dissipate after the bullet left the barrel... It worked very well.. The reason the military rejected the enhanced bolt carrier for shorter barreled rifles was because it was not reliable with rifle length gas systems (too low of residual pressure to reliably cycle the rifle length gas system) and they didn't want to have two types of carriers in the supply system..
When the bolt unlocks, the extractor lifts completely off the case rim and is dependent on the same residual pressure to hold the case against the face of the bolt until the extractor lowers back down to allow extraction....
A good example of residual pressure would be an air hose..When an air hose is plugged into a compressor, the air hose is charged..When you unhook the air hose, the air escaping from the hose is residual pressure..
Balancing the residual pressure is what determines a reliable gas system and there are different ways to approach this..Which one is optimum is what creates a great many debates on gun forums..