One thing I've posted before: use the "Dollar-Cost-Averaging Method" applied to stocks to also buy ammo.
Example 1:
If you buy ammo at $1000/case because your supply was low, do it, but keep an eye out for a better deal afterward.
If you can find the same ammo at $850/case, buy it. Now you have 2 cases of ammo at an average cost of $925 each.
If you find it again at $700/case, buy it. Now you've purchased 3 cases at an average cost of $850.
So, even though you spent $1,000 for one case, you've been able to lower the average for that case by $150. That means 2 of 3 cases were at or cheaper than the average, so overall, you've saved money.
Example 2:
Now, if you modify this slightly, you'll make out even better.
At $1,000/case, get HALF a case.
At $850/case, get a WHOLE case.
At $700/case, get 1-1/2 cases.
You'll have purchased less ammo at the highest prices and more at the lowest prices. You still wind up with 3 cases, but now 2-1/2 cases were at or below the average price. Only half a case was purchased at the highest price.
In the second example, you'll have 3 cases for which you paid a total of $2,400. In the first example, the same 3 cases cost you $2,550. You saved another $150 by varying the amount of ammo purchased at each price point.
If the market rises again, you can divest yourself of any excess ammo at or above the average price you paid. Or, just keep a good size stockpile to avoid having to buy at higher prices when (not if) the ammo market skyrockets again.
BTW, you don't have to buy each case/partial case all at once as long as the prices are in the same general range or lower for each purchase.