[lurkingknight]

only the pantac rrv I think has a fully integraded back piece/hydration carrier so you might be stuck having to replace the whole setup. It's possible there are other back panels you can get that include the shoulder straps that you can integrate to this rig, but that might trap you into spending money for this specific rig that you can't use elsewhere.

If you are already considering a gun that uses different mags, it may not be a bad idea to start putting together that taco rig. The TT rigs aren't terribly expensive from somewhere like dstactical, the tacos add up real fast.