As someone who is still working on developing their basic collection (i.e. no "safe queens," no "fun guns," only guns useful for training or fighting), I agree that rifles need more mags than pistols.
It must be nice to have $1,000 worth of magazines just for your 1911, with who knows how many more for each of your other guns, as some posters here do... but for those of us who have limited resources and are trying to prioritize, I would suggest the following:
Fighting rifle - minimum 10, desirable 20 (at least as many as you can reasonably carry, and it would be nice to have that many again in reserve).
Fighting pistol - minimum 3, desirable 5-10 (this is your SIDEARM. To me, silly to have more magazines for your sidearm than your primary weapon... again, at least as many as you can carry ALONG WITH your primary mags, and twice that number is desirable).
CCW pistol - minimum 2, desirable 4-6 (must have one plus one backup for carry, and additional spares are a good thing)
Anything with a maximum magazine of 10 rounds, like .22lr pistols or rifles (both of mine only have 10 round magazines available) - these aren't a priority, as they will be around when the next ban hits. Buy threatened stuff first. Still, it's nice to have at least 2 per each.
One thing I'm starting to realize is that, if I ever need a fighting rifle, I won't be able to carry 2+ rifles, or probably even 2+ fighting pistols, for that matter, so I'm investing in the ONE rifle and ONE pistol that I choose to have ready for that purpose. I'm set up, ready to hit the door, for my rifle with 10 mags total (280 rounds in my case - 8x30, 2x20), my sidearm with 5 mags total (40 rounds here), and the rest of my necessary fighting gear.
I do have one other fighting long gun, but it's not a rifle - it's a 'gague, and it would stay behind unless I had someone I trusted to back me up with it... which I don't where I am now, unfortunately. As much as I'd like to expand to more fighting rifles (AK, second AR, SKS, etc.), I'm not sure what the benefit of that would be before I complete the rest of my kit and invest everything I can into my 2 primary weapons.
In short, I think it's better to have just one excellent fighting rifle and fighting pistol with more than enough magazines, ammo and experience for each, along with the other important gear, than it is to have 3+ fighting rifles and 3+ fighting pistols, neither of which are at their full potential, stocked with enough magazines & ammo or trained fully with.
I'm not saying you only need 2 guns - but I am now investing everything I can into those 2 before I move on to the next.
With that said, I'd like an AK around November 4, if things go the way I'm expecting