@ Ironwolf,
i have been informed that its only the HK mags that will work in the HK416, I my self have not tried it. I have also bought one from Land warrior and it is a good buy and defo worth the money....if u have any further Questions i will be happy to answer just either post on here or PM me if u wish....I will be doing a full review soon so watch this space/facebook
lol
hope it helps