I've been scouring the interweb looking for a storage core for my Magpul MOE grip that holds 3 spare rounds. For some reason everyone that sells AR accessories sells the AA, AAA, CR123 and Bolt and firing pin cores, but NOT the 3 spare round one. I have to assume it's no longer manufactured. Does anyone have a line on where I can buy one of these cores? It seems like a great option to have a few spare rounds at hand, you never know, right?