Excellent quality and extra magazine - FAB Defense GL CORE MAG CP - M4 Survival Buttstock w/ Built-in Mag Carrier

Perfect for loading an extra magazine, it is always better to have an extra magazine and not need it than to need it and not have it, of course the rifle weighs a little more, for me it works perfectly and if you don't want to carry an extra magazine you simply don't put it in, without a magazine it really weighs almost nothing, if after a few months of use and everything works well, I would buy it again for others