Ammo will be in short supply during any grid-down situation , and the only rounds you’re likely to have are the boxes in your storage (which is why you should stock up more than adequately).
Even so, you may still be able to procure ammo via trade with other people, and in those cases, the ammo that was the most popular before the grid went down will be the easiest to find and trade.
Though no one can predict the future, it’s likely that these will be the most common rounds in a grid-down situation:
.22LR (also handgun): Without a doubt, this will be one of the most valuable calibers in a grid-down situation. With its popularity, low recoil, quietness and versatility, the .22 should be one of your top priorities when it comes to stocking up  on ammo.
.223 Remington/5.56x45mm NATO: This took up the biggest market share for rifle ammunition last year due to AR-15s being the best-selling rifles in America. If that’s not enough, this is a current military round.
.30-30 Winchester: A lot of Americans today still prefer the traditional lever guns, so there’s no doubt that the classic .30-30 will be in high demand.
7.62x39mm: AK-47s are both feared and respected, and along with it, the 7.62x39mm. With the ban on certain imports from Russia, it’s unclear about the future of this round, but for now American manufacturers seem to be producing more than enough of it. Even if you don’t have an AK yourself, other people do, making this ammo a valuable commodity for trade.
.270 Winchester: Quite a few American shooters swear by the venerable .270 to this day, and for good reason.
.308 Winchester/7.62x51mm NATO: The .308 has overtaken the .30-06 as the most popular big-game hunting caliber in the lower 48, but the margin is still razor thin. Also, as a current military round, the .308 will be one of the most important calibers circulating.
7.62x54mm: Chambered for such Soviet weapons as the Mosin Nagant , a very cheap and popular surplus rifle.
.30-06 Springfield: The enduring “thirty aught-six” will remain as traditional as steak and apple pie. It may have since been phased out by the military, but that hasn’t diminished the .30-06’s popularity with everyday people. The caliber is easily available and at fair pricing.
.300 Winchester: An excellent combination of high power and high velocity, the .300 Winchester has proven itself to be worth considerable respect. Many hunters have turned to the caliber for this reason.
.410 Bore: The .410 has seen a resurgence in recent years due to the popularity of revolvers chambered for the round, such as the Taurus Judge and the S&W Governor.
20-Gauge: When shooters demand a lot of stopping power but not the recoil of the 12-gauge, the 20-gauge is their next bet. Even if you don’t own a 20-gauge, having a box or two could tip the scales in a trade.
12-Gauge: The most popular shotgun round without a doubt is the 12-gauge. Heavily favored by the military and by civilians for hunting and home-defense, the 12-gauge easily took up the largest market share for shotgun ammunition last year.
.380 ACP: One of the most popular concealed carry rounds on the market.
.38 Special: Popular since the late 1890s, the .38 Special shows no signs of decreasing popularity. Adding to their appeal is that they can also be loaded in .357 Magnum revolvers.
9mm: Not just one of the most abundant pistol rounds, but one of the most abundant calibers of anything you can find. Affordable, accessible and versatile, the 9mm took up the biggest market share of any caliber in the United States last year. You should have a 9mm pistol without question, but even if you don’t, stock up on this caliber.
.40 S&W: Heavily favored by police departments around the country, the .40 S&W may have come a step behind the 9mm in terms of current market share, but it will still be one of the more prominent pistol calibers available.
.357 Magnum: This is the most popular chambering for large frame revolvers, bar-none. .357s also have reputations for being one-shot man stoppers, heavily contributing to their status.
.45 ACP: One of the most enduring pistol calibers of all time, the .45 ACP has a well-deserved reputation. Next to the 9mm, the .45 ACP has the biggest market share among pistol calibers.
.44 Magnum: This round is legendary for a number of reasons. In terms of accessibility, it’s expensive but still used by many shooters.
Which calibers do you believe will be most available? Share your thoughts in the section below: