Circle_10
08-28-18, 17:58
With regard to aspects of the difference between carbine, Mid-length, and rifle gas systems?
My current understanding of the subject is:
Due to the shorter distance between the chamber and the gas port in a carbine length gas system, the weapon begins to extract the fired case while pressures in the chamber are still high, and the fact that the extractor has to act against these pressures in order to extract the case is why carbines benefit from "enhanced" extractor springs (The Colt gold springs) and inserts (Including the rubber donuts in some cases) in order to ensure reliable function.
Because of the increased "dwell time" resulting from the longer distance from the gas port to the muzzle, a 16" carbine is also going to be over gassed compared to a 14.5" or shorter carbine. This is why 16" carbines in particular benefit from heavier buffers, to help slow the bolt velocity down as it cycles.
Sometimes a carbine that is too over gassed will actually "outrun" the magazine, leading to the bolt failing to lock open on an empty mag (which is a malfunction more often associated with short stroking from being *under*gassed).
With greater distance between the chamber and gas port, the chamber pressures at the time extraction begins are lower in a Mid-length gas system, and lower still in a Rifle length gas system.
Do I have this generally correct?
My current understanding of the subject is:
Due to the shorter distance between the chamber and the gas port in a carbine length gas system, the weapon begins to extract the fired case while pressures in the chamber are still high, and the fact that the extractor has to act against these pressures in order to extract the case is why carbines benefit from "enhanced" extractor springs (The Colt gold springs) and inserts (Including the rubber donuts in some cases) in order to ensure reliable function.
Because of the increased "dwell time" resulting from the longer distance from the gas port to the muzzle, a 16" carbine is also going to be over gassed compared to a 14.5" or shorter carbine. This is why 16" carbines in particular benefit from heavier buffers, to help slow the bolt velocity down as it cycles.
Sometimes a carbine that is too over gassed will actually "outrun" the magazine, leading to the bolt failing to lock open on an empty mag (which is a malfunction more often associated with short stroking from being *under*gassed).
With greater distance between the chamber and gas port, the chamber pressures at the time extraction begins are lower in a Mid-length gas system, and lower still in a Rifle length gas system.
Do I have this generally correct?