Does anyone have any experience with a Sig mcx hybrid (mcx upper, Sig 400 lower w/adapter.) There's one video on you tube from a dealer but very little other info on the web about these. They're a lot cheaper than a full mcx and about the same price as a mcx upper receiver. I really like the idea of the mcx platform but want more info before I make the plunge. Any information or food for thought would be greatly appreciated, also if anyone has an mcx in 300blk that they might want to trade for multi guns let me know. Thanks.