I purchased the 30 carbine boxes. They are too big in length and width (by about half a cartridge). Leaving you with falling over cartridges and a mess (if you load below capacity), or a box that doesn't close.properly (if you do). In any case you're not going to get the kind of polished, production looking box that you were hoping for (and if you're retentive enough to want these, instead of just throwing your ammo into a big bag like a slob, then you probably want them to look reasonable). I do not know if other calibers suffer this problem.After wasting hours trying to find a packing algorithm that works, I tried the loader, which is made out of the weakest possible PLA. It broke immediately. By the third box three pieces had broken off. The whole idea of using the loader for 30 carbine is probably not reasonable given how the box ears are suposed to fold over.Spend a bit more and get real shell holders, or make your own cardboard boxes to a size that actually fits. .Edit: after a few more hours, found a way to stack the cartridges to fit. The trick is the followingalternate directions for one row (heads to tails)then, on the next row, rotate everything 90 degrees and do the same - heads to tails. Raising review to three stars just because I don't have to burn the box. It's very slow work.