I'm going to agree with more mags.
I carry a rifle and a pistol. 3 pistol mags, and then as many rifle mags as I can stash on me. The pistol is only used if my rifle goes down while I'm engaging at close range. If you can reload your primary from cover, there is no reason to draw the secondary when you're out of it's effective range.
Ár skal rísa, sá er annars vill
fé eða fjör hafa. Sjaldan liggjandi úlfur
lær um getur né sofandi maður sigur.