A couple of days ago I was thinking that since I have 900 rounds of bulk .223 ammo, I should get a .50 cal ammo can to put it in. The way military 5.56 ammo is packed nowadays is in 4-pocket bandoliers, with 3 10-round clips in a cardboard sleeve in each pocket. That's 120 rounds per bandolier, and there are 7 of them in a can for a total of 840 rounds, and 2 cans to a crate. The bandoliers have a white thread near the bottom. If you rip the thread out, the pockets will be deep enough to put 30 round mags in. Way back in the old days

we had 7-pocket bandoliers with 2 clips in each pocket in a different kind of cardboard sleeve. So there were 140 rounds per bandolier instead of 120 like now, and it only took 6 of them to make 840 rounds. Now, as then, each bandolier has a safety pin on it to adjust the length of the strap, and there's a clip guide for each bandolier. I'm not sure there was always one for
every bandolier, but there was at least 1 or 2 per can and whoever got one was told not to throw it away. They always had someone else loading all our mags, so all I did was grab full mags at the range on the rare occasions I had to qualify. I know my 900 rounds in 6 extra heavy duty Ziploc bags will fit in a .50 cal ammo can if 840 rounds in clips in cardboard sleeves and bandoliers will fit, but I read somewhere that 1,200 loose rounds will fit in a can. I have no idea how many loose rounds will fit in the smaller 7.62mm can, but 420 rounds in clips and bandoliers will fit in one. So, maybe 500-600 rounds?