Recently I tested and compared a recent generation LMT enhanced carrier with the standard carrier in a 16" midlength MRP. The ammunition used was Federal and IMI M193. The only variables during this test were the carrier and a cam pin, and I doubt the cam pin would have changed anything significantly; all other components, including the bolt (an LMT enhanced), remained the same. Buffer tube used was standard carbine, not a VLTOR. The parts were cleaned and fairly well lubricated beforehand.
The primary difference I noticed was that whereas the rifle previously ejected to about 1:30 with 5.56 ammunition, the gun is now ejecting to approximately 2:15 to 2:30. While not totally bizarre, this was not what I expected, as I had read that the carrier velocity usually increases with the Enhanced carrier. Ejection pattern doesn't tell everything of course but I would assume that a shift backwards in a properly functioning gas system would usually imply slower cycling.
It seems there are a lot of people on this board who are much more knowledgeable than I on this subject, so I had the following questions:
1. Is this the usual behavior when installing an enhanced carrier in such a system? I have seen it suggested that the enhanced carrier tends to bleed off more gas with higher powered rounds, whereas with underpowered loads the extended cam pin track helps the gas system accelerate the carrier longer in spite of the extra vent holes. In effect, the Enhanced BCG does a better job of "self-regulating." Certainly other tests with adjustable gas blocks would suggest the latter benefit does exist, but I have found less on whether the EBCG may actually reduce carrier speed with higher pressure loadings.
2. If indeed the EBCG does reduce carrier speed with full power 5.56 loadings in this gas system, would this reduce reliability with 5.56 pressure cartridges in cold & dirty conditions, since the carrier is getting less momentum in spite of the easier extraction? Or would such inoptimal conditions replicate the effect on an underpowered round to some extent, in that the longer "action time" during lockup would help the carrier move along?
3. I know that the gas entry hole from the key into the carrier is bifurcated. Is the divider located on the key, or on the carrier itself? I would assume it would be on the carrier itself to maintain parts commonality and for simplicity's sake. Wanted to ask as I had a gunsmith replace the factory key with another, standard mil-spec key. (Factory key had been dented during an unrelated incident, no fault of its own.)
4. Since the stress and forces involved during extraction are reduced, and the carrier seems to be moving more slowly, would the EBCG be reducing recoil slightly in this instance? I didn't really notice anything significant but it would make logical sense.
Bookmarks