Kobalt, if he's your, SHTF, Bug Out or Tribe buddy, I would think that both of ya'll training with the M4 would be good for now, as there are two of them. If something were to happen and you needed to work as a team, you will want to be able to trade mags in a fight.
But... if you buy an AK, then ya'll could chose to both train with that.
My thing is that it doesn't matter. Just chose the firearm that you both want to use in SHTF, and then both of you just practice the hell out of that.
Also, if you're going to do any sniper stuff, both of ya'll can learn both the sniper rifle, and the spotting.
As far as the rifles, though, just pick one and train like hell on both using it, and working together to own some targets.
