FYI I have run 2 of these stocks with the Lantac bcg that came in the Gun with the sabre stock. I have seen no problems in them whatsoever. As stated I think the caution comes from the other NIB bcgs I have sworn off several of them not due to size as much as the shit coating on several, I wont name names but they are popular bcgs but have seen flaking, corrosion etc on several. I have not experienced this with the Lantac, it is more expensive but seems to be worth the extra $$$ for the quality. Just my 2 cents, both guns are bad556-lw guns