Berger is between a rock and a hard place. They are running 3 shifts, producing all they can. They can't keep up with demand in all sizes and weights all the time, but the demand isn't high enough to justify new facilities. Their QC slows them down, which is GOOD. All I can tell you is to stock up when they are available. I keep 4 boxes of 6.5 and 2 boxes each of 270 and 308 on hand. I replace as I use, but if they aren't available, I have several months supply to fall back on....
That's the best advice I can give you. And they aren't cheap, I built my supply by adding a box every time I ordered. Instead of buying all at one time.
Robbin