I don't know but isn't every day a day to stock up?
People that have been shooting for any length of time should know that things happen, ammo prices go up and sometimes it's hard to find. If you pick up a 100pack or three from wally world every week you are going to accumulate a decent stash.
Buy it cheap and stack it deep. I don't think you can ever have too much ammo. I'm still shooting SA battle pack 5.56 from the 90's. Back then it was $300 shipped for a 2700 round tub or $36 for a 300 round battle pack. Yeah, i bought a bunch.