Sorry......I haven't gotten around to it......
There's a crap load of ammo needing to be shucked of its cardboard and migrated into ammo cans, but I haven't quite worked up the courage, yet.
This time I hope to compare the density differences between retail packaging vs loose vs stacked in the 50 cal cans and put the data in a table.
In trying to uncover my table saw, I've finally been forced to tackle the ammo consolidation issue again. So, after shucking a ton of cardboard and plastic, here's the round counts I came up with.
.223.30 CanLoose: 690-700
Interlaced: 822
Stacked: 712
.50 CanLoose: 1270
Interlaced: 1444
9mm.30 CanLoose: 1280-1300
Stacked: 1438
.50 CanLoose: 2320
Stacked: 2520
.308.50 CanLoose: 680-760
Interlaced: 680
After the initial comparison, I went with the loose fill method for the rest.
Interestingly, I found that doing the interlaced stacking method for the .308 resulted in increased dead space and thus was a less efficient fill method. The same was not true of the smaller dimension .223 rounds, which is more efficient interlaced when compared to either loose or simple stacked methods. There must be a mathematical explanation for this. For explanation of what I mean by interlaced, look at the picture of the .308 ammo in my OP.
I have the most confidence in the .308 numbers because while I was consolidating my Malaysian and German surplus I kept better track of the round counts by counting the individual 20 and 40rd boxes over multiple cycles. The 9mm and .223 numbers came primarily from loose packed bulk buys and was harder to count accurately.

This Malaysian stuff has very little dead space due to arranging the cardboard boxes in an irregular pattern that's so tight they tied a ribbon around two of the boxes so you can pull them off the bottom. Using 13x 40rd boxes and 1x 20rd box they fit 540rds in a standard .50 can. By removing these rounds from their cardboard boxes and loose filling them (keeping the long axis of the ammo can and cartridges parallel) I took 4 x 540rd ammo cans and consolidated them down to 3 x 720rds cans, which frees up a can to put the German stuff in.

Removing surplus German MEN and DAG 20rd boxes from their 200rd battle packs I could fit 28 x 20rd = 560rds in a .50 can.

The surplus Hirtenberger comes in more rectangular 20rd boxes that are sealed in plastic inside a 240rd cardboard case with carrying strap, which fits perfectly inside a .30 can. These 20rd boxes are just slightly bigger than a current retail PMC Bronze cardboard box, of which I am unable to fit more than 24 x 20rds = 480rds into a .50 can.
I whole-hardheartedly recommend against doing any of this! It's a shit-ton of work, even without the precise stacking I did when I started this thread, which is why I've procrastinated on doing it again. I'm paranoid so I wind up shredding all the cardboard that indicates they contained ammo, in case the garbage truck spills my can on the street for all my neighbors to see, so it takes longer than just dumping rounds in an ammo can. Handling all that cardboard shreds your fingers, too. It's been great for getting through a bunch of audiobooks, though.